A contribution to meteorology by Spencer Cowper, Dean of Durham 1746–74

Joan M Kenworthy, Margaret S McCollum


The writer of a hitherto unnoticed letter dated 17 January 1770, which was received by the National Meteorological Library and Archive, which was received in 1935 by the National Meteorological Library from the Radcliffe Observatory, Oxford, has been identified as Spencer Cowper, Dean of Durham from 1746 to 1774. In the letter Cowper summarizes the weather observations he made in Durham in 1769, provides a short but masterly analysis of the regional climate and refers to the completion of a naturalist's journal, which he planned to send to Oxford. This paper makes the case that the recipient of the letter was almost certainly Thomas Hornsby, first Radcliffe Observer, whose links with Durham are fully explored. Investigation of the context in which the letter was written reveals the hitherto neglected range and depth of Spencer Cowper's scientific interests and connections. The journal to which Cowper refers has not yet been traced despite extensive searches, but, through an examination of the development and use of naturalists' journals during the late 1760s and of the wider national and regional context of data collection and observation evident in correspondence between those involved, new light is shed on Spencer Cowper's likely awareness and associations, some of which are evident in the newly analysed catalogue of his books and scientific instruments that were offered for sale after his death.

The letter

In the National Meteorological Archive at Exeter is a letter,1 headed ‘Durham. Jan. 17/70’, in which the writer, identified as Spencer Cowper, Dean of Durham (figure 1), mentions the completion of a ‘naturalists Journal’ for 1769 that he plans to send to Oxford, summarizes the weather observations in his journal and reflects on the character of the Durham climate (figure 2 and Appendix 1). The letter is included in a group of papers received by the National Meteorological Library2 from the Radcliffe Observatory, Oxford, on 10 January 1935. The letter first excited our interest because the instrumental observations predate any previously found for Durham City, but it is rather more intriguing in bringing to light an aspect of Spencer Cowper's interests that has not previously been identified by researchers, both in the context of contributions to provincial natural history and meteorology by gentlemen and clergy in the second half of the eighteenth century,3 and in the context of his own activities in theoretical astronomy. We hope that our attempt to suggest possible circumstances in which the letter was written might encourage the identification of further relevant material, perhaps even the naturalist's journal itself.

Figure 1

The Hon. Spencer Cowper DD, Dean of Durham 1746–74. Undated portrait in oils by an unknown artist. Reproduced by kind permission of Durham Cathedral. (Online version in colour.)

Figure 2

The letter from Spencer Cowper, Dean of Durham, probably to Thomas Hornsby, first Radcliffe Observer, dated 17 January 1770. (The figure continues overleaf.) (Reproduced by kind permission of the National Meteorological Library and Archive, Exeter.)

The letter in the National Meteorological Archives is not included in a collection of Dean Cowper's correspondence published by Hughes, which consists chiefly of the dean's letters to his brother, the second Earl Cowper.4

The dispersal of papers from the Radcliffe Observatory

In 1935 the astronomical work of the Radcliffe Observatory (now part of Green College) was transferred to South Africa, only the meteorological observations continuing under the direction of the Oxford School of Geography.5 During the consequent disposal of papers and astronomical instruments and the much-regretted dispersal of the Rigaud Library,6 some material went to the Bodleian Library, some to Corpus Christi College, Oxford, instruments and various papers to the Oxford Museum for the History of Science, other papers to the Royal Astronomical Society, and those relating to the Oxford meteorological record to the Oxford School of Geography. Only a few papers concerning meteorology went to the National Meteorological Library, including the letter from Spencer Cowper.7

Despite widespread protest, the Radcliffe Trustees entrusted a sale of books from the Observatory to Sotheby & Co. and the final sale took place on 7 May 1935. No reference to a naturalist's journal or any other document dated 1769 has been found in the Sotheby's catalogue for that sale8 and we have so far found no reference elsewhere to the deposit of a 1769 naturalist's journal with entries for Durham.

The writer: Spencer Cowper, Dean of Durham

We have established that the writer of the letter was the Honourable and Reverend Spencer Cowper DD (1713–74),9 Dean of Durham from 1746 to 1774, younger son of William Cowper, first Earl Cowper (1665–1723) and his second wife, Mary Clavering (1688–1724), and brother of the second Earl.

Spencer Cowper is remembered for his poetic10 and musical interests11 rather than for his scientific leanings, although, as we show below, the latter seem to have been underestimated by recent writers. His poet cousin, William Cowper, wrote:Humility may clothe an English dean,That grace was Cowper's—his confess'd by all—Though placed in golden Durham's second stall.12

The not very clear ‘Sp’ in the signature to the letter (Figure 2) was first read as ‘J M’ or ‘J N’, but comparison with a letter from Spencer Cowper held in the University Library at Durham confirms that the handwriting and signature are those of the dean. This is not the only time that his signature has caused uncertainty. A letter from him to the Durham astronomer Thomas Wright (1711–86) was once thought to be from his cousin, the poet William Cowper, when ‘Sp’ was mistakenly read as ‘W’.13 However, Spencer Cowper, who was an amateur astronomer, had long been acquainted with Thomas Wright.14 Wright published a theory of the weather and made weather observations during 1783 from his observatory tower, now described as Wright's Folly, in the village of Westerton outside Durham.15 We have no evidence that he influenced Cowper's weather observations in 1769, although Wright had returned to County Durham, where he was born, in 1762. Certainly, Cowper's interest in astronomy may have been stimulated by his friendship with Thomas Wright,16 although Taylor suggests that there was also a family interest in mathematics, in that ‘a Spencer Cowper, presumably uncle to the dean, had been a subscriber to Harris's Lexicon Technicum in 1704’.17

Spencer Cowper's aspirations in science

The Durham Cathedral Chapter in the late 1760s included several members of academic distinction and interests, with wide connections, some with Oxford; examples are Dr John Moore, a canon of both Christ Church and Durham, and later Archbishop of Canterbury; Robert Lowth, Bishop of Oxford and from 1777 Bishop of London, who was Professor of Poetry at Oxford and a well-known biblical scholar and Fellow of the Royal Society; William Warburton, Bishop of Gloucester, a prolific author and biblical controversialist and friend of Alexander Pope's; Charles Weston, canon of St Paul's, London; and Newton Ogle, Dean of Winchester.

There is little doubt that, although more usually associated with sermons, poetry and cathedral music, Spencer Cowper also had aspirations to be counted as a scholar and a man of science. His father, William Cowper, the first Earl, was elected a Fellow of the Royal Society in 1706, and his brother William Clavering Cowper (1709–64), the second Earl, was elected in 1732.18 His nephew, the third Earl, George Nassau Clavering Cowper (1738–89), a collector of scientific instruments as well as an art collector and patron, was elected a Fellow in 1777, after Spencer Cowper's death.19

Spencer Cowper contributed letters to the Royal Society: one addressed to the President on the earthquake of 8 March 1749 with a note on a luminous arch observed on 16 February 1749,20 and another addressed to his brother William, Earl Cowper, on the surprising behaviour of water in ponds at the time of the Lisbon earthquake in November 1755.21 He may have hoped that his more substantial work in theoretical astronomy would bring him scholarly recognition.

The need to determine longitude had influenced mathematicians and astronomers from the late seventeenth century22 and, in 1754, Cowper published his first contribution on the parallactic angle23 with lunar tables intended for use in the calculation of longitude at sea, in the form of a letter to the President of the Royal Society,24 although we have no evidence that the letter was read at a meeting of the Society. His calculations were intended to further tables previously provided by Halley, and his conclusion suggests that he intended his work to be a contribution towards further elaboration by him and others: ‘What these few pages contain, though very imperfect, may perhaps supply some hints not useless towards a further Correction of the Lunar astronomy, which is all, one so slightly versed in the Science can pretend to.’ Unhappily, the inclusion of his tables, rightly or wrongly modified by Robert Heath in Astronomia accurata,25 led to withdrawal of support from the publication's subscribers and disappointment for Cowper. Not only were there unpleasant accusations of inaccuracy, but there were still more upsetting accusations that he had taken his figures from Mr Mayer's Lunar Tables.26 Heath had dedicated his Astronomia accurata to Cowper, included a number of notes initialled ‘SC’, and praised Cowper's equations, referring to him as the first Englishman to resolve easily the central equation of the Moon.27 In his preface, Heath concluded with lines of verse entitled ‘To the Encouragers and Improvers of Arts & Sciences’:Though loss of sacred Science is deplor'd,That Treasure by a Cowper is restor'd.

Cowper clearly intended his further publication with revised tables in 176628 to justify his previous work. He gives as the first motive for it, ‘That this small Tract upon the Parallactic Angle, which he still fondly hopes has been found to have its utility, might be laid before the Public free of those errors and inaccuracies, which the hastiness of the first publication, and his absence from the press, had occasioned in the former impression.’ This second publication is dedicated to Admiral the Hon. George Townshend, Admiral of his Majesty's Blue Squadron,29 and Cowper states that he would be disappointed in his hopes if the Admiral did not ‘admit the DURHAM TABLES to share the Credit of having conduced your own Preservation and that of the Squadron you command, along with Mr. Harrison's TIME-KEEPER and the NAUTICAL EPHEMERIS.’30 His deep-felt wish for justification and recognition is expressed in introductory encomia to ‘ASTRONOMY’ and to the ‘ROYAL SOCIETY’. Cowper believed that his tables ‘for Conciseness as well as Correctness’ would ‘excell all others, as yet published’ and that, were they ‘exceeded by Tables more correct, (such as Mayer's Tables, now in Possession of the Commissioners of Longitude, may be supposed to be)’, he was confident that ‘the Public will be so just to think that to have done so much will not be a work entirely void of Merit’. He adds in his own defence that ‘the Comment had been wrote, and the Tables (computed from the Elements therein established,) nearly completed, before Mr. Mayer's Tables were brought over to England; at least, before they came to the author's knowledge’ and mentions that this was not the ‘only Discovery, which two Persons have made at the same time unknown to each other’. Despite these admissions and his expressed confidence in the usefulness of his tables, Cowper must have been bitterly disappointed once again with the limited attention his efforts apparently received.31

The carrier of the letter and the likely recipient

Dr Moore, who was to take the naturalist's journal to Oxford when he returned from Durham to Oxford, has been identified as Dr John Moore, canon of Christ Church, Oxford, and Durham, mentioned above. That Moore was in Durham at about that time is confirmed by his marriage (his second) to Catherine, daughter of Sir Robert Eden, third baronet, of West Auckland, County Durham, on 23 January 1770, in St Mary the Less church, Durham.32

Enquiries made of Christ Church in the hope of identifying Dr Moore's contacts in Oxford revealed only dates when he dined in hall.33 It is reasonable to suppose, however, that the letter was addressed to Thomas Hornsby (1733–1810), first Radcliffe Observer from 1772, that the letter reached Hornsby at his college (Corpus Christi), and that it was subsequently taken by him to and remained at the Radcliffe Observatory from the time that he moved there to the dispersal of the Observatory papers in 1935.

Hornsby was appointed Savilian Professor and Reader in experimental philosophy (astronomy) in 1763. After his successful appeal to the Radcliffe Trustees for funds to build an observatory, Hornsby moved with his family to a house on the site of the Observatory towards the end of 1773,34 when the first astronomical instruments were installed in a wing of the Observatory building. His meteorological observations from the site began in 1774.35 Work on the central block was not completed until 1799.36

Hornsby had made astronomical observations at his college, at the tower of the Schools, at his residence in New College Lane and at Blenheim Palace in Oxfordshire, and there is ample evidence that he took an interest in meteorology, not merely because astronomers needed temperature data when correcting for refraction.37 It seems from his papers that, as early as 1758, he was ‘pondering the best form in which to maintain a meteorological journal’38 and was experimenting with ways of measuring rainfall at Corpus Christi College in 1758 and 1760.39 He made numerous but irregular observations of temperature, rainfall, winds and cloud from 1760 until 1804, when his health and eyesight were failing.40 As discussed below, he advised others on instruments and methods of observing and became involved, albeit marginally, in a project to create a network of weather observers across Britain.

Moreover, Hornsby had proven connections with Durham and would almost certainly have known Spencer Cowper. Records of the Royal Society state that Hornsby was from Oxford, but Ruth Wallis41 has shown that, although the date of his birth is uncertain, he was baptized in Durham in the parish of St Nicholas on 27 August 1733 and was the son of Thomas Hornsbie (or Hornsby), an alderman of the City, and his wife Thomasine. The burial of Thomas Hornsby the elder on 7 July 1771 was recorded in the register of Durham Cathedral. We have traced the will of Thomas the elder, made on 25 October 1770 and proved at Durham in 1771,42 in which he referred to ‘my Eldest son Thomas Hornsby of the City of Oxford Professor of Astronomy’. Wallis suggests that the younger Hornsby's interest in astronomy might have arisen from hearing Thomas Wright lecture in Durham, and that he would have come to know Spencer Cowper through his father and during his years at Durham School, which has a strong connection with the cathedral. Wallis admits that Hornsby's name does not appear in the published registers of Durham School, but we have discovered that the records of Corpus Christi College, Oxford43 state that he was admitted to the college as the scholar for the diocese of Durham on 21 November 1749, aged 16 ‘on or abouts 18 August last past’. Although the Durham scholarship at Corpus was open to boys from anywhere in the diocese, Hornsby's two immediate predecessors as Durham scholars had both attended Durham School. A further link between the Hornsby family and Durham Cathedral arose through Thomas Hornsby's younger brother, the Reverend Nicholas Hornsby, a graduate of Merton College, Oxford, who from 1768 until about 1770, covering the period of Cowper's journal, served as curate of St Mary the Less church in Durham, situated in the lee of the cathedral, just a few hundred yards from Cowper's deanery.44

Wallis suggests a link between Cowper's work and Hornsby's work on the parallactic angle.45 By his own account and from the evidence of his publications in 1754 and 1766, Cowper had been at work on his calculations for more than 10 years, probably beginning when Hornsby was in his early twenties. Hornsby published his work on the parallactic angle in 1763 and 1771, and first appears in the list of those attending a meeting of the Board of Longitude on 4 August 1763,46 when, as the newly appointed Savilian Professor at Oxford, he had become an ex officio member of the Board.

Although it remains possible that the letter was written to someone other than Hornsby and was later donated to the Observatory, we know that at a later period such items were generally marked as such and would have been kept only if pertinent to the work of the Observatory.47 There is mention that the recipient had been in Durham in a previous year or years (‘you experienced this yrself being with us’). Although travel had become easier by the mid eighteenth century,48 family commitments and time-consuming activities in Oxford may have prevented Hornsby from making frequent visits to his father, but there is evidence of a visit in the dedication of two editions of Armstrong's map of Durham in the inscription: ‘N. Latitude 54° 46′ 50″ taken by Mr. Professor Hornsby in 1765’.49 The letter from Spencer Cowper seems at times to address someone with less knowledge of the local climate than might be expected of Hornsby, who was brought up in Durham, yet the formal style of letters between gentlemen in the eighteenth century might explain this. Certainly, we can dismiss the formal beginning—‘Dear Sir’—as having significance, and, as reports of scientific enquiry were often made in the form of a letter intended to be shared or read at a meeting of the Royal Society, it is possible that Cowper, who had previously contributed such letters, had such a possibility in mind.

Another candidate we considered as recipient of the letter is Thomas Pennant (1726–98), the traveller and naturalist,50 who visited Durham in the summer of 1769 on his first tour of Scotland.51 Though known rather more for his zoological work and the published accounts of his excursions, Pennant developed an interest in the natural history of areas he visited, particularly in geology and mineralogy, as part of his antiquarian pursuits. In appendices to the account of his first tour are two lists of ‘queries’, the first addressed to the ‘Gentlemen and Clergy of North Britain respecting the antiquities and natural history of their respective parishes, with a view of exciting them to favour the world with fuller and more satisfactory account of their country, than it is in the power of a stranger and transient visitant to give’, and another relating to the natural history of the parish, but making no reference to regular weather observations. As discussed below, Pennant was involved in encouraging the use of Daines Barrington's naturalist's journal of 1767, but his ‘queries’ do not refer to it. Pennant met Thomas Wright on an excursion made in 1773.52 However, we have found no evidence that he wrote to Spencer Cowper before 1769 or met him later, or that he was in Oxford to receive a letter in January 1770.

Attempts by Clergy and others to develop a network of weather observations

In January 1770 Cowper writes that he had completed his ‘naturalists Journal’ for 1769 as well as he could, which suggests that he did so in response to a request. It seems likely that a request came from Thomas Hornsby, but there were others, also in contact with Hornsby, who were concerned to extend the use of naturalists' journals and, in particular, the coverage of weather observations over the British Isles.

The Royal Society was receiving meteorological reports from various quarters in the late eighteenth century, although the Society holds nothing from Durham. One contributor was the Reverend William Borlase (1696–1772), the antiquarian and naturalist, who made meteorological observations at Ludgvan, Cornwall. His correspondence housed in the Morrab Library, Penzance, has been extensively examined by Oliver53 and includes letters from Borlase to Hornsby on instrumentation and times of observation, referring to advice from Hornsby to Borlase.54 These encourage us to think that Hornsby may also have been advising Cowper. Hornsby made Borlase a ‘rainfall-collecting vessel’, sent him a specimen of his Oxford record for a period in December 1758, and visited Borlase in Cornwall on 28 July 1770.55

One of the items in the group of papers received by the National Meteorological Library from the Radcliffe Observatory in 193556 is a letter from Borlase to Hornsby dated 12 August 1767,57 together with meteorological observations for 1766, 1767 and 1770 at Mount's Bay, Ludgvan.58 Borlase refers to a new ‘Metal-Scale’ and to its position—‘facing a window which bears N: half E. about 4 inches from the glass, as you advised. It has no walls round it so that the Sun can neither directly nor indirectly affect it’. He comments on his times of observation, adding ‘thus far the placing and time of Observing the Therm:r is nearly as you desired’.

Borlase also corresponded with Charles Lyttelton (1714–68), Dean of Exeter from 1748, Bishop of Carlisle from 1762, and President of the Society of Antiquaries from 1765 to 1768, and with Jeremiah Milles, Dean of Exeter from 1762 and President of the Society of Antiquaries from 1769.59

Oliver tells us that ‘Borlase and Lyttelton were concerned with attempts to broaden the extent of the coverage of the British Isles by reliable weather observations’.60 He quotes a comment by Borlase to Hornsby that Lyttelton's ‘unequalled correspondence in the several parts of Britain’ was ‘in great hopes of promoting such observations as will in a few years be very serviceable to Nat. Knowledge’.61 Borlase and Lyttelton consulted the President of the Royal Society on the need for a record from the north of Scotland.62 Borlase rejoiced that Hornsby's data would represent the ‘middle of the island’. In March 1767, Hornsby offered to procure ‘a register from Lancashire and perhaps from near Abingdon’.63 It seems possible that it was in this context that Hornsby (or Borlase or Lyttelton64) encouraged Spencer Cowper to make weather observations and complete his journal. That Cowper knew Lyttelton through the church and their similar concerns for cathedrals is clear, and is confirmed by his mention of a visit from Littleton (sic) in a letter to his brother dated 29 October 1756.65 No correspondence between Borlase and Cowper has been traced,66 but the inclusion of Antiquities of Cornwall 1769 by Borlase in Cowper's library (see the section on the catalogue of his library below) shows that Cowper was aware of Borlase's work.

The use of Naturalist's Journals

Cowper refers to the summary of his weather observations as ‘the result of the whole’, which suggests that he included only weather observations in his journal and did not enter a broader range of comments on natural history. It may be no mere coincidence, however, that Daines Barrington (1727/8–1800), the judge, antiquary and naturalist,67 published a set of blank printed forms in 1767 entitled Naturalist's Journal.68

Barrington's set of forms was first printed anonymously by Benjamin White, the brother of Gilbert White, whose letters to Barrington and Pennant comprise the well-known Natural History of Selborne. Each page of Barrington's pro forma covers one week, with five columns out of ten for weather observations of temperature, pressure, wind, rain, snow or hail, and comments on the weather. In a preface, Barrington acknowledges his debt to the botanist Benjamin Stillingfleet (1702–71),69 who had proposed the idea of keeping a detailed calendar of natural phenomena over time, but it was Barrington who recognized the need for a common format if any useful analysis was to take place.70

Although Gilbert White may have been inspired to begin his Garden Kalendar by Thomas Barker of Lyndon Hall, Rutland, whom he visited in 1751 when Thomas Barker married White's sister Anne,71 he later adopted the format of Barrington's Naturalist's Journal, Barrington having sent him a copy in 1768—very possibly at Pennant's suggestion, because White had corresponded with Pennant earlier.72 The nearness of the date of publication of Barrington's pro forma in 1767 and Cowper's completion of a journal in 1769 suggests that Cowper used a copy of Barrington's pro forma or that his awareness of it led him to call his journal by the same name. What is particularly important is that a copy of ‘The Naturalist's Journal 1767’ appears in the catalogue of Cowper's library sold in 1775, after his death in 1774.73 It is possible that it was the one in which Cowper entered his observations, if it was not taken to Oxford as he had planned, although one would expect the seller to have noted that it contained observations made by Cowper. It has not yet proved possible to ascertain the fate of the copy that was included in the sale, and the name of its buyer, if any, is unknown.

Another clerical recruit to keeping a naturalist's record, though not in Daines Barrington's pro forma, would seem to be Shute Barrington, the brother of Daines, who had a later connection with Durham as Bishop from 1791. He included observations of the weather in the diary that he kept at his home at Mongewell, Oxfordshire, which he acquired in 1770.74 The first entry for Mongewell, dated 1 September 1770, comments that ‘The thermometer hung upon a tree 3 feet from the ground on the north side …’.75

A catalogue of Cowper's library, prints and mathematical instruments

The catalogue of Spencer Cowper's library, prints and mathematical instruments offered for sale in January 1775, after his death in 1774, provides a guide to his extraordinarily wide connections and interests,76 even though we cannot know whether some were inherited as part or the whole of a family collection, or gifted, perhaps by visitors to the deanery. Included are collections of classical and English literature, foreign literature, history, geography, theology, antiquarian works, law dictionaries, and a wide range of books concerning science, mathematics and astronomy, together with, understandably, many copies of volumes of his sermons.

It is also encouraging that copies of ‘Pennant's Tour in Scotland 1771’77 (lot 533), Daines Barrington's ‘The Naturalist's Journal 1767’78 (lot 668) and a copy of ‘Borlase's Antiquities of Cornwall 1769’ (lot 508) are listed in the catalogue of the sale, indicating that Cowper was aware of the existence and activities of these men.

Spencer Cowper's meteorology

It is possible that Cowper obtained a thermometer from Hornsby. It would probably have been a mercury thermometer and a separate instrument, not one attached to his barometer,79 although there was no thermometer in the collection of instruments sold after Cowper's death. It is strange that he does not comment on whether his thermometer was hung indoors or out of doors. A visit to the deanery in Durham and a study of the layout of rooms in the deanery through time80 does not clarify where he could have sited his instruments indoors. Hornsby wrote to Borlase on 3 March 1767 about the use of an outside thermometer, but it was more normal to hang a thermometer indoors in an unheated room.81 If Cowper made observations in the deanery, it might have been in the east-facing library, in the north-facing morning room, or in what was called King James's room, which is also north-facing. Those rooms are on the first floor. At ground level were found the ‘camera inferior’, or servants’ dining room, which faces south, and the chapel.

Throughout much of his tenure of the deanery, as was not uncommon at that period, Cowper spent only three months of the year in Durham, usually in autumn,82 but he began to spend much more of his time there from 1767.83 We cannot be sure that he made weather observations himself or that they were made every day without fail by him or a by member of his staff, although he reduced values for the seasons with apparent confidence in a full record. We do not know what advice he was given, if any, on how to place his instruments and when to make observations, but he would certainly have been familiar with the observation of temperature in relation to astronomical observations. His ‘Difference of the Extremities’ is a range of 20.8°F between the mean of afternoon observations during 20 March to 22 September (60.5°F) and the mean of the morning observations during 22 September to 20 March (39.7°F). The observations may have been made at 8 a.m. and 2 p.m. throughout the year, the morning observations being chosen to represent winter and the afternoon observations summer to give a particular impression of seasonal range.84 Dr Peter Rowntree offers another suggestion, however; namely that the observations may have been made at 2 p.m. only in the summer half year, if the exposure of the thermometer meant that readings would be affected by the Sun at 8 a.m. in summer. If observations were made indoors, heating by fires could have been a problem by 2 p.m. in winter.85 We should expect mean indoor temperatures to be warmer than outdoor temperatures over the year as a whole, although in summer a temperature recorded at 2 p.m. would usually be higher out of doors than indoors.

Without knowing the exposure of his thermometer, no comparison can be entirely meaningful, but Cowper may have arrived at a not unreasonable indication (50.2°F) of the mean indoor temperature for Durham in 1769. It may have been calculated from 12 monthly means or from daily values, because it represents with slight inaccuracy the mean of his seasonal values (60.5°F and 39.7°F), or the mean of his highest and lowest values in July (77°F) and January (24°F). As an indication of mean outdoor temperature, 50.2°F would be somewhat high. However, Dr Rowntree offers a possible explanation for that. The average of the July maxima and January minima for Durham in the period 1906–35 is 49.9°F, whereas the mean of the January and July averages of maxima and minima is 48.3°F. The difference when using two six-month periods would be less but still substantial, so that a somewhat high estimate of the mean temperature for Durham in 1769 is to be expected from Cowper's method of calculation. Moreover, analyses of data where hourly data are available, give values for the mean of 8 a.m. and 2 p.m. that are above the 24-hour mean.86 If one uses hourly means for each month, the mean of values for 2 p.m. from April to September and for 8 a.m. for the rest of the year is also higher than the annual daily mean.87 On this evidence, Cowper's annual mean, although high, could represent outdoor conditions. Scrutiny of the Central England Temperature (CET) series88 confirms that winter was relatively mild and summer cool in 1769, but the series also shows that 1769 was cooler on average (47.8°F) than 1761, 1775 and 1779 (when the estimated CET values reached or exceeded 50°F). Manley's extended series for Durham gives mean values that range from 44.1°F to 49.2°F for the period from 1801 to 1850.89 Manley gives a mean value of 47.7°F for 1769 in his series for ‘Lancashire’.90

With regard to Cowper's extreme temperatures, Dr Rowntree has once again suggested useful comparisons. Cowper's lowest temperature of 24°F on 23 January compares well with Gilbert White's value for Fyfield of 22°F on 22 January 1769, which was almost certainly an outdoor observation, whereas London data given in Gentlemen's Magazine give a much higher minimum of 33°F on 23 January, most probably observed indoors.91 The 3 July extreme of 77°F is high for an indoor observation92 but may be low for an outdoor temperature at 2 p.m. For example, the maximum screen temperature observed at Durham University Observatory in the period 1850–1947 was 89°F on 16 July 1876. Thus we remain uncertain whether the exposure of Cowper's thermometer was indoors or out of doors.

Cowper's pressure values are reasonable, although his minimum is low and he makes no mention of correction to sea level.93 He would have used a mercurial barometer, because the aneroid barometer had not yet been invented. Who made the barometer we cannot determine. It is thought that Hornsby used one made by the famous instrument maker, J. Bird, who supplied most of the astronomical instruments for the observatory in Oxford.94 McConnell suggests that Cowper's barometer might have been a ‘banjo’ type, but was more likely to have been a stick barometer, because by that time a simple siphon was used without the complexity of float-and-string to rotate the needle around a dial, and it could have been made locally from a siphon tube sent from London, or he might have had a high-quality instrument sent from London.95 It is possible that Cowper had possessed a barometer for some time—we need not suppose that he obtained one especially to make observations in 1769. Nicholas Goodison says that a barometer was ‘a widely owned piece of furniture’ by the 1790s.96 The professional and upper classes would have led the way early in this habit. Frustratingly, no barometer is included in the sale of Cowper's instruments.97 It is possible that it remained after Cowper's death as a piece of furniture in the deanery, but there is no knowledge in Durham today of an eighteenth-century barometer that once belonged to Spencer Cowper. It is also possible that the barometer was taken by his nephew, the third Earl.98

Cowper says that he has no ombrometer with which to measure the quantity of rain,99 but his ‘meer Conjecture’ that a mean for Durham could be around 30 inches, although high, is not unreasonable, the mean annual rainfall for Durham being just under 26 inches.100 He notes the rain shadow effect of the Pennines—‘The Great Rains that come from the atclantic are stopt before they reach us by the Western Hills and fall on the Counties of Cumberld and Westmd with great violence’. His comments that rain at Durham (‘oftenest’ and known to him to happen for ‘three days continued’) comes with east or southeast winds rising up against the Pennines, and that the heaviest rains fall at the time of ‘a rising Glass’, describe occasions when an anticyclone to the north forces depressions to follow a southerly route bringing moist onshore easterlies to the northeast of Britain, sometimes accompanied by heavy snow in winter.

Cowper recognizes late springs as a particular characteristic of the northeast, although he attributes them entirely to the effects of easterly winds and not explicitly to the coolness of the North Sea at that season—‘the same Cause which brings in the Easterly Winds in the Spring occasion here their longer stay and checks it so that its progress is very slow’. Gilbert White mentions a sudden change from 7 May 1769 induced by incoming cold air,101 supporting Cowper's comment that in 1769 easterly winds checked the progress of spring despite its early onset.

Cowper refers to the ‘solour’ or ‘solar’ force with the confidence of a theoretical astronomer. The use of this phrase often relates to theories of gravity,102 but we can assume here that he means the proportion of incoming radiation compared with the maximum possible ‘at a maximum in the Zenith’. Ascribed to him also is A perpetual table of the sun's rising and setting for the City of Durham.103

In comparing winter temperatures at Durham favourably with those in London, he may have recognized that for London the distance from the western ocean and the nearness to mainland Europe have a cooling influence in winter. He is also identifying, although perhaps unconsciously, the marked absence of maritime influence in the Thames valley during the periods of prolonged frosts, ‘some of which nearly cover'd the Thames with Ice’, when the weather was less severe in Durham. Cowper's perception of the climate of Durham was no doubt influenced by those few years when he was in residence throughout the seasons, but those of us who live in Durham are as sensitive as he was to the fact that winter weather can sometimes be less severe in the northeast than in the southeast of the country.104

Cowper's final summary suggests that in theory he would have expected Durham to be cooler in winter and warmer in summer than he had actually experienced, the ratio between the values of the solar force for London and Durham being greater in winter than in summer, when the longer days in the north give closer values for the two latitudes. In that context, summers in the north are disappointing.

Cowper may have had sight of The Fruit-Garden Kalendar by John Laurence, Rector of Yelvertoft, Northamptonshire, and later Rector of Bishopwearmouth, County Durham 1720–32,105 perhaps even the copy that is now in the Bamburgh collection106 of Durham University Library at Palace Green, although its provenance is unknown. Laurence calculated the ‘Degrees of the Sun's Heat’ according to its altitude for various latitudes between 44° and 56° N. However, whereas Cowper writes that ‘Clouds, Wind and Rain perpetually break in on our Summer Months, and check the ripening of our Grain and Fruits’, Laurence suggests that the long days of the northern summer aid the ripening of fruit, because ‘during all the Summer Season … betwixt the Two Equinoxes, there are no less than One Hundred Hours of Sunshine at Durham, more than there are at Plimouth …’. Perhaps by ‘sunshine’ he meant daylight.

In his will, Cowper left his copy of John Flamsteed's Historia Coelestis107 to the Dean and Chapter Library in Durham and instructed his executors108 to sell his ‘mathematical instruments’, among other items, to provide bequests to servants and ecclesiastical acquaintances, but no meteorological instruments were included in the sale. His hygrometer features in it but is likely to have been used in connection with astronomy. Moreover, Cowper's possession of a hygrometer does not signify the use of thermometers, as wet-and-dry-bulb psychrometry was not practised by weather observers until the mid nineteenth century.109

Eighteenth-century meteorology and Spencer Cowper's contribution

Allen110 suggests that, in the absence of a society to which they could belong,111 naturalists were obliged to develop networks of correspondents. Lists of ‘queries’ were commonly circulated in the middle of the eighteenth century, many being similarly worded and clearly derivative of one another. Some lists included questions about the weather or ‘state of the air’ and its relation to health, and asked whether a register of weather was being taken.112 The efforts of Borlase and Lyttelton to create a network of weather observers should be seen in this context. After the relative failure of efforts by James Jurin and others earlier in the century,113 however, attempts to improve the availability and quality of weather records in the second half of the eighteenth century again achieved little. It was all too easy for people to slip away from their involvement. Oliver suggests that it may have been ‘too much a case of the converted corresponding amongst themselves’.114 We have no evidence that Cowper continued his journal in 1770. Hornsby, whose health was poor, had many other commitments.115 Lyttelton died in 1768 and Borlase in 1772. Moreover, Barrington's dream of comparative studies made possible by the use of his Naturalist's Journal was not realized.116

Feldman117 draws attention to an abrupt change from 1770 with the establishment of some national observation networks in Europe and the publication of substantial papers on meteorology, whereas in Britain the keeping of a continuous meteorological record began at Kew in 1773 and at the Royal Society in 1774. Feldman typifies the earlier part of the eighteenth century as a period when there was a lack of synthetic vision, a failure to characterize the climate of places or integrate the collection of places studied into the notion of a region. He refers to two groups who alone discussed regions: plant and human geographers and—a category into which we can surely place Spencer Cowper—‘mathematicians who calculated the effects of the Sun's heat on different parts of the earth’, but Feldman claims that neither group drew on weather observations.

By choosing 1770 as the turning point before which, he suggests, interest in meteorology had fallen off, Feldman underestimates the developing understanding evident in mid-century in the letters of William Borlase. Granting that an element of scientific immaturity is suggested in Borlase's ‘Parochial Queries’ of 1752, when he includes a question, possibly derived from some other questionnaire, about monstrous births, human or brutal, within the same section as the question ‘Have you, or any neighbouring Gentleman you know, made any observation towards forming a Register of the Weather?’, we can nevertheless see the ability of Borlase to characterize the climate of places in a letter he wrote 10 years later (on 20 September 1762) to console Lyttelton on the disagreeable weather of the far north, after his appointment to Carlisle. Borlase wrote, ‘The climate may not be so gentle as what you left, but the supple mind of the prudent and contented confirm readily to the present, and I doubt not makes you not less happy in the Summer frosts of Cumberland, than in the mild and soft Springs of Exeter.’118 It is also remarkable how much understanding of regional climate is shown in Cowper's carefully composed and perceptive letter, making us wish that we could see the more detailed observations in his journal and any comments he may have made on the weather day by day. He used interesting methods of comparative analysis and marshalled his facts to convey the climate of a place in its regional setting and provide an intelligent description of local and topographical effects. By contrast, another observer in northeast England, James Losh, who kept meteorological observations at Jesmond Dene, Newcastle, from 1801 to his death in 1831, did not analyse his data, although he commented on the weather at home and, when he had been away from home, on the weather elsewhere.119

We can excuse the weather observers of the eighteenth century and early nineteenth century if they ran out of energy and enthusiasm. It was difficult to find a use for accumulated data without a unified method of observation—which was not achieved until the middle of the nineteenth century—and a theory of weather, which was still rudimentary in the last part of the nineteenth century and was not truly achieved until the early twentieth. All too often, data were collected with little thought about an ultimate purpose,120 and meteorologists were arguing about the merits of Baconian or Humboldtian inductive methods well into the nineteenth century. On 18 July 1763 Borlase comments with extraordinary perception that his and Lyttelton's scheme for obtaining records from widely separated places to send to the Royal Society for comparison and preservation ‘may in time either facilitate some more perfect theories of winds and weather in our climate, or, which is altogether as likely, show the uncertainty and vanity of all such attempts…’.121

Unless further records or relevant correspondence are found, we must assume that Spencer Cowper regarded his weather observing as a one-year project and not a continuing commitment. His concern to identify ‘Cause’, his awareness of change over time—‘at least of this year’, ‘whereas in former years’—and his interest in local influences—‘The narrowness of this part of the Island, and the mountains that divide the Western part of this County from Cumberland and Westmoreland’—make us wish that he had continued to observe and comment on the Durham weather after 1769.


That Spencer Cowper was among those contributing weather observations in the eighteenth century has not previously been recognized, and his letter of 17 January 1770 is a valuable contribution to the relatively neglected story of the attempts in the mid to late eighteenth century to develop a network of meteorological observations in Britain. It is unfortunate that the letter has previously lain idle and that his naturalist's journal has been discarded, lost or ignored. The evidence we have found strongly points to Thomas Hornsby, Radcliffe Observer and Savilian Professor at Oxford, as recipient of the letter. His Durham connections and likely acquaintanceship with Spencer Cowper suggest that he would have encouraged Cowper's decision or willingness to keep a naturalist's journal or weather diary in 1769. Although we have not found any conclusive evidence that others influenced Cowper's involvement, it is clear that Cowper knew Charles Lyttelton and, as we can see from the catalogue of his library, it is also clear that he was aware of the activities of Daines Barrington and William Borlase. It is likely that, despite or because of his own previous disappointment at the reception received by his lunar tables, Cowper would have been pleased to join a project with those whose scientific and antiquarian interests he respected. All those we have mentioned were elected Fellows of the Royal Society—Milles in 1742, Lyttelton in 1743, Borlase in 1750, Hornsby in 1763, and Pennant and Barrington in 1767.

The letter also adds to what is known of Spencer Cowper's scientific interests and capabilities. His sincerity of purpose seems to have been combined with an equal concern for recognition of his scientific pursuits. In his publication of 1766,122 he writes:When we find we have been equal to the task, and that our labours are brought to the wished for conclusion: then the sense of a good intention animates the pleasures arising from Public approbation, for the Mind feels an inward approbation, much more satisfactory to it than the greatest external applause; the applause of a good conscience. This dilates the heart, and fills it with gratitude towards that being, from whose bounty he derives the powers, and disposition of doing good; and thence gaining the praise of mankind.

Was his contribution to the study of the Durham climate another occasion when Cowper's scientific efforts and achievements were ignored by his contemporaries? Did Hornsby reply to the letter or discuss the instrumental observations with Cowper on a visit to Durham? Was Cowper's analytical and descriptive skill overlooked? Was the effort he had made to keep a journal for a year unappreciated? Did his journal reach Hornsby in Oxford, or was it not given to—or was it forgotten by—Dr Moore, perhaps remaining in Durham until after Cowper's death? Is there a possibility that the journal and further correspondence relating to Spencer Cowper's weather observations will some day be found?


We should like particularly to thank Dr Anita McConnell, formerly of the Science Museum and the Oxford Dictionary of National Biography, for her enthusiasm, advice and generous help in our searches and enquiries. We should also like to thank the following for their invaluable help: Archivists at the County Record Offices of Flintshire, Hertfordshire and Warwickshire; the Archivist and the Librarian at Queen's College, Oxford; Linda Atkinson, Librarian at the School of Geography, Oxford; Graham Bartlett, National Meteorological Library and Archive; the Dean and Chapter of Durham; Ms Barbara Dodds, Secretary to the Dean of Durham; Dr Matthew Eddy, Durham University; Gill Edwards, Librarian, Green College; Norman Emery, Durham Cathedral archaeologist; Matthew Greenhall, research student at Durham University; Mrs Elizabeth Knight, Trustee at The Cowper and Newton Museum, Olney; Ian McGregor, National Meteorological Library and Archive; Linda Musser, Librarian, Penn State University; David Pedgley, Royal Meteorological Society; Julian Reid, Archivist at Corpus Christi College, Oxford; Dr Peter R. Rowntree, Hadley Centre (retired); Professor Tony Ryan, Green College, Oxford; The Very Revd Dr Michael Sadgrove, Dean of Durham; John Simmonds, honorary archivist at the Morrab Library, Penzance; Brandt Vogel, USA; Dr Dennis Wheeler, Sunderland University; and Joan Williams, Assistant Cathedral Librarian, Durham.

Appendix 1. Transcript of the letter from Spencer Cowper held in the National Meteorological Archive

Durham. Jan. 17/70

My Dear SirI have compleated my naturalists Journal for 1769 as well as I cou'd. When Dr Moore returns to Christ-Church I will trouble him with it. In the mean time you may be glad to see the result of the whole.Embedded Image

By the Thermometrical observations you will see how very mild our Winters are, or at least of this year; and at the same time how much below par our summers. The Difference of the Extremities being only 20,8. The narrowness of this part of the Island, and the mountains that divide the Western part of this County from Cumberland and Westmoreland account for both the one and the other. Clouds, Wind and Rain perpetualy break in on our Summer Months, and check the ripening of our Grain and Fruits. The Month of July this year was the only summer month we had. August and Sepr, were wet and cloudy, and some days of those Months Cold, whereas in former years, July has been a wet Month, and Aug. and Septr our best Summer. But you experienced this y[ou]rself being with us, so I need say no more. May and June excepting a few days were cold: the same Cause which brings in the Easterly Winds in the Spring occasion here their longer stay and checks it so, that its progress is very slow. This year it began as forward as I ever saw it in Hartford shire but towards the middle of May the Easterly Winds broke in and checked all Vegetation for near three weeks, so on the whole it was very late. We have had very little Frost either at the begining or latter end of the year: and I am certain that the Cold in general falls much short of that near London or Oxford. I have been here in several contin[u]ed frosts, some of which nearly cover'd the Thames with Ice, and I dont recollect four days in each, when the Farheneit has been lower than 24. and commonly near noon above the friezing point. The Sky commonly overcast, and towards the Middle of the day the frost visibly relaxing, especialy in the Streets. You know, I have no Ombrometer to measure the quantity of Rain, but I shoud judge we have not much more than in the South, or rather we stand at a mean between the quantity in Essex and Lancashire, or at about 30 Inches: but this is meer Conjecture. The Great Rains that come from the atclantic are stopt before they reach us by the Western Hills and fall on the Counties of Cumberld and Westmd with great violence. Our Rains oftenest come with an East or South East Wind, these mountains then stoping the Clouds, and heaping them upon us. I have known three days continued Rain from that point. Our heaviest rains come with a rising Glass; instances of which you will find in my Journal, which I will refer you to, asking you pardon for taking up so much of y[ou]r time with these slight observations. But I cannot help observing how different the degrees of heat and Cold between London and Durham are to that which comparing the solour force at each place woud teach us to expect, which I formerly computed as belowEmbedded Image

  • Received December 3, 2007.
  • Accepted March 26, 2008.


  1. National Meteorological Archive, Exeter, ARCHIVE Y15.K3 ID6A [41].

  2. The letter was transferred from the Library to the Archive after the move of the Meteorological Office and the National Meteorological Library and Archive to Exeter in 2004.

  3. See, for example:

  4. The papers, in a folder marked as having been received by the National Meteorological Library on 10 January 1935, are listed as: Meteorological observations, Durham, 1769; St. Michael's Bay, 1766, 1767, 1770; Whitehaven, 1845 (J. F. Miller); Utrecht, 1853 December – 1858 November (Buys Ballot).

  5. We are grateful to Linda Atkinson, then Librarian of the School of Geography, Oxford, and Professor Tony Ryan of Green College, Oxford, for this information.

  6. Op. cit. (note 9).

  7. Truth, by William Cowper (1731–1800).

  8. In

  9. T. Wright, ‘Speculum meteorum: or An essay towards establishing a true theory of the weather analogous to that of the tides’, Wright MSS 15 (1785), Durham University Library; M. J. Tooley, Thomas Wright of Durham 1711–1786, Exhibition Guide, University of Durham Library, 17 (1993); Hughes, op. cit. (note 14).

  10. See a letter from Cowper to Wright of 11 November 1753, requesting his assistance in solving a problem regarding the projection of the eclipse, Pierpont Morgan Library (New York), Department of Literary and Historical Manuscripts, Oversize 106329 MA 86.

  11. However, neither could be described as ‘scientist’, probably having obtained Fellowships through influence and Court connections. The first Earl, created baron in 1706, became the first Lord Chancellor of Great Britain 1707–1710 and was a prominent Whig.

  12. Povey, op. cit. (note 10), pp. 40–41, includes a poem written by Mr Arden and collected by Dean Cowper that is a satire on Clavering-Cowper and says that the dean often mentions his nephew with disapproval—see Hughes, op. cit. (note 4).

  13. Cooper [sic], op. cit. (note 13), pp. 647–649.

  14. For one of many accounts of the impact of the longitude problem on developments in astronomy and the establishment of observatories, see

  15. The angular difference in the direction of an object when viewed from different positions.

  16. In a letter to the Rt Hon. Earl of Macclesfield, President of the Royal Society

  17. Cowper describes his disappointment in his second publication on the same theme: S. Cowper, ‘A treatise on the parallactic angle, extracted from a letter to the late Earl of Macclesfield on that subject. To which is added an appendix: containing a compleat set of solar and lunar tables, entitled Tabulae Dunelmenses, for computing the places of those luminaries, both in, and out of syzigies’, London, 1766, Durham University Library SC00479. ‘Syzigy’ or syzygy in this context refers to the conjunction of the Moon with the Sun.

  18. Op. cit. (note 17).

  19. Op. cit. (note 26).

  20. In 1743 Spencer Cowper married Dorothy, daughter of Charles ‘Turnip’ Townshend, second Viscount, by the latter's second marriage to Dorothy Walpole, sister of Robert Walpole. The Admiral George Townshend was the eldest son of Charles Townshend by that marriage. See J. K. Laughton, ‘Townshend, George (1715/16–1769)’ (rev. Ruddock Mackay), Oxford Dictionary of National Biography (Oxford University Press, 2004). It seems from that article that the Admiral had no service at sea after 1757.

  21. The lunar tables of Tobias Mayer were submitted in 1755. Cowper was clearly aware that, at a meeting on 9 February 1765, the Board of Longitude had discussed the sums to be awarded to Harrison and Mayer (in the latter case to his widow), and that Nevil Maskelyne had testified to the usefulness of the lunar-distance method for finding longitude at sea and proposed the practical application of this method by a nautical ephemeris with auxiliary tables and explanations. Royal Society MS/244, Maskelyne Papers.

  22. Op. cit. (note 26), preface and p. 16. We have found no evidence that his paper was considered by the Board of Longitude.

  23. H. M. Wood and W. Greenwell, The registers of St. Mary in the South Bailey, Durham (1908).

  24. We are grateful to Dr McConnell for making this enquiry of the archivist of Christ Church College on our behalf.

  25. He did not publish these observations and the continuous meteorological record of the Radcliffe Observatory dates from after Hornsby's time in 1815. See G. Wallace, ‘Meteorological observations at the Radcliffe Observatory’, in Burley and Plenderleith, op. cit. (note 22), pp. 103–128.

  26. Dr McConnell writes that the surviving records of meteorological observations precede those of astronomy at Blenheim Palace, where an observatory was set up in about 1780 by George Spencer (1739–1817), fourth Duke of Marlborough. The Radcliffe Observatory in Oxford was built and equipped by the Radcliffe Trust on land provided by the Duke, on whom Oxford had recently conferred an honorary doctorate, and it was under Hornsby's tuition at the Radcliffe Observatory that the Duke learnt his observing technique on the fine suite of instruments by John Bird.

  27. Op. cit. (note 38).

  28. Durham University Library, DPR I/1/1771/H26/1–2.

  29. Admissions register CCC O B/1/3/5. Information by courtesy of Julian Reid, archivist to Corpus Christi and Merton Colleges, Oxford.

  30. Durham University Library Archives and Special Collections DDR/EA/CLO/3/1768/13 and DDR/EA/CLO/3/1769/7: papers relating to the ordination of Nicholas Hornsby as deacon [October] 1768 and priest, 24 September 1769.

  31. Op. cit. (note 41).

  32. Cambridge University Library, MSS Royal Greenwich Observatory 14/4. We are grateful to Dr McConnell for this information.

  33. A. V. Simcock, private communication from the Oxford University Museum for the History of Science.

  34. D. E. Allen refers to the importance for developments in natural history of improvements in travel and communications resulting from the turnpike acts from 1850, better maps, better horses and better coach springs, in ‘Natural history in Britain in the eighteenth century’, Arch. Nat. Hist. 20, 333–347 (1993), also reprinted in D. E. Allen, Naturalists and society (Ashgate Variorum, Aldershot, 2001).

  35. The county palatine of Durham, surveyed by Capt. Armstrong and engraved by Thomas Jefferys geographer to his Majesty, editions by R. Sayer & T. Jefferys (1768) and by John Cary (1791), Durham University Library, Special Collections. Perhaps coincidentally, lot 5 in the Prints and Drawings section of the sale of Spencer Cowper's books, etc., after his death was a copy of Armstrong's map of Durham (see note 73).

  36. T. Pennant, A tour in Scotland, 1769 (1771, reprinted by Birlinn, Edinburgh, 2000).

  37. T. Pennant, A tour from Alston Moor to Harrowgate and Brimham Craggs (edited and published by his son David Pennant, London, 1804).

  38. Ibid, p. 288.

  39. Simcock, op. cit. (note 47) has suggested a likely circumstance for the contact between Hornsby and Borlase: Hornsby used accommodation for his lectures in the (now Old) Ashmolean Museum, the present home of the Museum for the History of Science. Borlase was a benefactor of the Museum and corresponded with the then Keeper of the Museum, William Huddesford, a keen naturalist; see also Oliver, op. cit. (note 53), p. 292.

  40. Op cit. (note 1).

  41. The letter begins ‘Dear Sir’, but concludes with ‘Mrs Borlase's and my best wishes attend you and Mrs Hornsby’.

  42. Listed as St. Michael's Bay, op. cit. (note 7). Borlase's meteorological observations for 1769, 1770 and 1771 (the last before he died) were published by the Royal Society in Phil. Trans. R. Soc. 60, 230–232; 61, 195–197; 62, 365–369 (1771–72).

  43. For an account of the network of antiquaries encouraged by Borlase, Lyttelton and Milles, see

  44. Oliver, op. cit. (note 53), p. 293.

  45. They may have known or received the Meteorological Register 1754–1774 presented to Perth Literary and Antiquarian Society by Thomas Soutar, extracts from which are filed in the National Meteorological Archive, Exeter, as ARCHIVE Y15. K3 ID6A [40], though not attached to the group of papers received from the Radcliffe Observatory in 1935.

  46. Oliver, op. cit. (note 53), pp. 292–293.

  47. Lyttelton died in 1768.

  48. Op. cit. (note 4).

  49. We are grateful to John Simmonds, honorary archivist of the Morrab Library, Penzance, where correspondence of Borlase is held, for this information.

  50. Gill Edwards, Librarian, Green College, first drew our attention to the copy of Barrington's Naturalist's Journal held by the Radcliffe Science Library, Oxford.

  51. Stillingfleet is best known for his introduction of the system of classification by Linnaeus to English botanists.

  52. From 1736, Barker kept a record of birds, trees and astronomy, and meteorological records that are well known to climatologists. See, for example:

  53. R. Mabey, ‘Introduction and notes’, in Gilbert White, The natural history of Selborne (Penguin, London, 1977), p. xiv.

  54. No. 668 in A Catalogue of the entire Library, Prints, and Mathematical Instruments, of the Honourable and Reverend Spencer Cowper, Dean of Durham, Lately Deceased. Which will be sold by Auction, by S. Baker and G. Leigh, Booksellers, at their House in York-street, Covent Garden, beginning Monday, January the 9th, 1775, and to continue the Six following Evenings. British Library S. C. Sotheby (1) [copy, annotated with details of purchasers and prices, also available on microfilm, Reel 5, 1775, January 9].

  55. B. Pedgley and D. Pedgley, Crowmarsh. A history of Crowmarsh Gifford, Newnham Murren, Mongewell and North Stoke (Crowmarsh History Group, Crowmarsh, 1990), pp. 43 and 140.

  56. Royal Society Library, Meteorological Archives, 262–313. Information from David Pedgley.

  57. Op. cit. (note 73).

  58. Op. cit. (note 51).

  59. Op. cit. (note 68).

  60. Private communication from Dr McConnell; A. McConnell, Barometers, 2nd edition (Princes Risborough: Shire Publications, 1994).

  61. G. W. Kitchin, The story of the Deanery, Durham, 1070–1912 (Thomas Caldcleugh, Durham, 1912).

  62. Op. cit. (note 53), p. 282.

  63. Op. cit. (note 9).

  64. Povey, op. cit. (note 10), p. 26, n.3, in which Povey cites ‘Letters’ (op. cit. note 4), p. 75, n.7, referring to the quarterly distribution of ‘dividends’ to members of the Cathedral Chapter that was recorded in the Treasurer's Books in the Durham Cathedral Muniments, now cared for by Durham University Library (DCD/L/BB). These show that until 1767 Cowper attended only the autumn distribution and for 1758–60 did not attend at all, but after 1767 he attended nearly all the distributions.

  65. Dr Dennis Wheeler remarks that Cowper's seasonal range is in effect an index of continentality, showing a relative lack of continentality in the north of England compared with the southeast of the country, where greater continentality is evident in the contrast between similarly cold winters but hotter summers.

  66. P. R. Rowntree, private communication.

  67. Rowntree used data for Kew and Aberdeen Observatories.

  68. Rowntree used data for Cambridge for this calculation.

  69. M. Hulme and E. Barrow, Climates of the British Isles, present, past and future (Routledge, London, 1997), p. 405. The series of Central England temperatures was originally constructed by Gordon Manley, ‘Central England Temperatures; monthly means 1659–1973’, Q. J. R. Meteorol. Soc. 100, 389–405 (1974) and later modified by D. E. Parker, T. P. Legg and C. K. Folland, ‘A new daily Central England temperature series’, Int. J. Climatol. 12, 317–342 (1992).

  70. J. M. Kenworthy, ‘The Durham University Observatory record and Gordon Manley's work on a longer temperature series for north-east England’, in The climatic scene (eds M. J. Tooley and G. M. Sheail), pp. 17–38 (George, Allen & Unwin, London, 1985).

  71. G. Manley, ‘Temperature trend in Lancashire, 1753–1945’, Q. J. R. Meteorol. Soc. 72, 1–31 (1946).

  72. Op. cit. (note 85).

  73. Rowntree has pointed to three indoor July maxima elsewhere for comparison, all lower than Cowper's value of 77°F.: Selborne 73°F, London 67°F and Exeter 69°F.

  74. The Durham Deanery is about 100 metres above sea level.

  75. Op. cit. (note 38).

  76. Op. cit. (note 79).

  77. N. Goodison, English barometers 1680–1860. A history of the domestic barometers and their makers (Cassell, London, 1969).

  78. Op. cit. (note 73).

  79. Op. cit. (note 19).

  80. Borlase also used the term ‘ombrometer’, but later called his rain gauge a hygrometer. Op. cit. (note 53).

  81. For the period 1961–90, the value for Durham is 649.9 mm (25.6 in) and, for 1971–2000, it is 643.3 mm (25.3 in).

  82. ‘The Naturalist's Journal’: the printed tabulated annual diaries, edited by the Hon. Daines Barrington; with records of the barometer, thermometer, wind, and weather, and remarks relating to gardening, agriculture, and natural history, entered from day to day by Gilbert White, of Selborne; 1768–1793. BL Add. 31,846. Vol. i. (ff. 180), 1768–73.

  83. Cowper uses the expression in a treatise on the parallactic angle: ‘In the Perihelion of the Earth, when the Solar Force is at its greatest …’ (Cowper, op. cit. (26)). Samuel Horsley states that he has ‘always been sensible that an extreme precision was requisite in determining the mean quantity of the solar force affecting the moon's gravity towards the earth …’ (Phil. Trans. R. Soc. 59, 153 (1769)); Linda Musser of Penn State University has provided us with a number of references in Phil. Trans. R. Soc., in which the ‘solar force’ is mentioned in the context of gravity and the attraction of Sun and Moon.

  84. S. Cowper, A Perpetual Table of the Sun's Rising and Setting; to every degree of Declination. For the City of Durham:—Latitude 54°: 47′: 30″(London, 1766), Durham University Library Pam XLL525.38COW. Cowper's name is not on the sheet, but Richard Gough states in British topography. Or, An historical account of what has been done for illustrating the topographical antiquities of Great Britain and Ireland (London, 1780), vol. 1, p. 340, that it was published by ‘the late dean Cowper’.

  85. Dr Dennis Wheeler writes that on occasions like those described by Cowper, the moderating effects of the North Sea induce cloudiness and a ‘raw’ feel to the air, so that the weather in the northeast may be less severe than in the southeast, but far less pleasant.

  86. J. Laurence, The Fruit Growing Kalender (London, 1718).

  87. Originating as the library of John Sharp (1643–1714), Archbishop of York, the Bamburgh library was held by his descendants, Thomas Sharp (1693–1758) and John Sharp (1723–92), both archdeacons of Northumberland and canons of Durham Cathedral, until John Sharp passed the library by gift (1779) and bequest (1792) to the Lord Crewe Trustees, who maintained it at Bamburgh Castle. Part was deposited in Durham University Library in 1938 and the rest in 1958.

  88. Cowper's copy held by the Cathedral Library is the 1725 edition. A copy of the 1712 edition of Historia coelestis Britannica by John Flamsteed (1646–1719), first Astronomer Royal, produced by a committee of members of the Royal Society against his wishes, using an imperfect version of his text, is held by Durham University Library at Palace Green and was donated by the Revd T. J. Hussey of Kent, the purchase of whose instruments enabled Durham to establish an Observatory in 1841.

  89. The National Archive PROB 11/996, fol.321

  90. Dr McConnell suggests that Cowper's hygrometer might have been a Saussure hair hygrometer or Deluc whalebone hygrometer.

  91. Op. cit. (note 48), p. 335.

  92. We can look to the foundation of societies after the period we are discussing, such as the Lunar Society of Birmingham in 1775, the Manchester Literary and Philosophical Society in 1781, and the Linnean Society of London in 1788.

  93. Jankovic op. cit. (note 3), pp. 107 and 211; Bibliotheca Topographica Britannica (London, 1780–90), vol. 1, no. 1, (i). From 1752, Borlase circulated sets of queries on parochial history in Cornwall, based on a model used in Wales and Yorkshire.

  94. A. Jacobo Jurin, ‘Invatio ad Observationes Meteorologicas Communi Consilio Instituendas.’ Phil. Trans. R. Soc. 32, 422–427 (1722); J. Jurin, ‘An invitation to form a meteorological system of observations by world-wide agreement’, Meteorol. Mag. 109, 272–274 (1980) (translated from the Latin by Dr J. G. Landels, University of Reading).

  95. Op. cit. (note 53), pp. 275, 295 and 296.

  96. Op. cit. (note 38).

  97. Although, among others (including Gilbert White), the poet Thomas Gray used Barrington's format for his record of daily weather from 1767; Jones, op. cit. (note 69), p. 351.

  98. T. S. Feldman, ‘Late Enlightenment meteorology’, in The quantifying spirit in the 18th century (eds T. Frängsmyr, J. L. Heilbron and R. E. Rider), pp. 143–177 (University of California Press, Berkeley, 1990), at pp. 147, 159 and 162.

  99. P. A. S. Pool, William Borlase (Royal Institution of Cornwall, Truro, 1986), pp. 234 and 298.

  100. ‘Meteorological observations made by James Losh, at Jesmond Grove, in the years 1802 to 1833’, vols 1–6, MSS, held in the Library of the Newcastle Literary and Philosophical Society.

  101. R. Sweet notes, ‘Both naturalist and antiquary had to work hard to counter the common supposition that the virtuoso collected objects with no discrimination, and with no higher purpose of intellectual enlightenment in mind’, in Antiquaries. The discovery of the past in eighteenth-century Britain (Hambledon & London, London, 2004), p. 9.

  102. Op. cit. (note 118), p. 252. Borlase refers to the atmosphere as ‘a various irritable mixture’, adding pessimistically, ‘no apparently similar circumstances will always produce the like, nor is any thing to be foretold from analogy and review’.

  103. Op. cit. (note 26).

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