Copy letter from Edward Sabine to Sir Humphry Davy, president of the Royal Society
Information
Title - Copy letter from Edward Sabine to Sir Humphry Davy, president of the Royal Society
Record type - Archive
Original Reference - RHS/Col/2/Z1/26
Date - 26 Aug 1822
Scope & content - Written from Maranham [Maranhao, Brazil]
This letter is referred to in Sabine's published work 'An Account of Experiments to Determine the Figure of the Earth', 1825
He last wrote to Davy from the Gambia, and hopes that Mr Browne [Henry Browne, husband of Sabine's sister Caroline] has been updating him on his progress and welfare since, and that the enclosures he has sent via Browne excuse the intermission in his correspondence; he has been completing on-the-spot abstracts of the principal observations he has made at each station, which is especially useful in Africa, where the risk of death adds extra importance to immediate note-taking; he hopes that Davy approves of his diligence; the move to the HMS Pheasant has extended his opportunities greatly; Clavering [Douglas Charles Clavering, captain of HMS Pheasant] has paid great attention to landing and re-embarking his instruments, and there have been no accidents so far; he took a second invariable pendulum as a precautionary measure, and has employed both instruments and obtained a double series of experiments at each station; the clock with the two solid pendulums, which he had with him on Parry's 1819 Arctic voyage [William Edward Parry, arctic explorer; Sabine accompanied Parry on his 1819 expedition], runs well and produces results that match those of the detached pendulums; the clock must have a fair trial due to the importance of corresponding results by different methods; the pendulum stations set up so far have been Sierra Leone at latitude 8°29'N, St Thomas's [Sao Tome, Sao Tome and Principe], 25 miles north of the equator, Ascension [Ascension Island, British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha] at 7°56'S, Bahia [Brazil] at 12°59'S and Maranham [Maranhao, Brazil] at 2°31'S; this makes four stations within 10° of the equator, and one a little beyond; Clavering intends to give him the opportunity to set up stations at Trinidad for the parallel of 10°, at Jamaica for 20°, at Bermuda for 30°, and at the Azores [Portugal] for 40°; London will suffice for a station near enough to the 50th degree; the purpose of this letter is to request an extension of the experiments towards the north in the summer of the following year; irregularities of local attraction in the superficial geological strata may exist but do not show any obvious external manifestation, thus sites cannot be chosen with regard to them, and the pendulum itself may be the only means of discovering them; these irregularities are the main difficulty in determining the figure of the earth, and the most probable method of removing their influence from his -data is simply to set up experiments in 'every diversity of circumstance' in order to neutralise it on the final result, with the only necessary constant being that they are all as close to sea level as possible; as such, the selection of locations for further experiments could be decided based on general convenience; he proposes that future stations could be a northern Scottish island for the 60° parallel, the south cape of Norway for the 70° parallel, and Spitsbergen [Svalbard, Norway] and a second location on the east coast of Greenland for the 80° parallel, as well as a fifth in Iceland at latitude 64; these experiments may be carried out easily if undertaken in that order; the Admiralty have proven their readiness to aid in his experiments and should provide a means of conveyance for the proposed future experiments; he thinks that the voyage could be of service to geographical knowledge, as the eastern coast of Spitsbergen and the eastern coast of Greenland above 72° have rarely been visited; a channel opens in the ice during the summer months, due to the tides and heat absorption by nearby land, through which they can pass to access lesser-known parts of the Greenland coast further north; the only voyage recorded to these areas is that of Hudson [Henry Hudson, 17th-century explorer and navigator] who reached 82°N, but the account is imperfect [Hudson actually reached 79°49'N, and thought that Svalbard's northernmost point that they could see was 82°N, but it was in fact 80°49'N]; the majority of people believe Hudson's tales to be false, but he considers him to be one of the navigators of that period in discovery who was discredited at the time but was justified in the end, and of whom we should be proud [Hudson's crew mutinied and set him adrift in Hudson Bay; his version of events from his last voyage was never heard]; if the shores of Greenland extend sufficiently northward, a passage should open in the ice to a higher latitude than they would ever be able to reach in the open ocean; this theory is supported with evidence from all previous expeditions to the Arctic Circle, in which passage has only been found close to land; they will only need to take one ship to the east coast of Greenland, rather than two as on northwest discovery voyages, as in the event of the vessel's loss they can take boats safely down the coast to Iceland; geographical exploration should come second to the pendulum experiments, as they must be undertaken by the same observer with the same instrument and without delay; he is concerned that if there is any restriction in time, it will be allotted based on the interests of the commander of the voyage rather than for its main purpose, and as such he requests that Clavering lead the northern voyage the following year as he is accustomed to aiding with the experiments [Clavering was in fact chosen to lead the expedition to Greenland and Norway on the HMS Griper in 1823]; he is very willing in turn to aid Clavering in his own maritime investigations, as the 'intimacy and confidence' they have would 'render such cooperation mutually agreeable', and he is familiar with northern navigation from his 1819 voyage with Captain Parry; he apologises for the long letter, but had he waited until seeing Davy in person the voyage would have been delayed until the summer of 1824, and he hopes to avoid postponing any part of the experiments; they will not arrive back in England before the middle of January, and he hopes to sail earlier in the spring than northern voyages usually do in order to reach Spitsbergen as early in the season as it is accessible, once the experiments in the 60th and 70th parallels are complete; he has enclosed an account of Breguet's [Abraham-Louis Breguet, Swiss horologist] chronometer between February and August as a continuation of the report he sent from the Gambia; he requests that a copy be sent to Breguet, as he may wish to replace the chronometer 'by one better prepared to enter in competition with British workmanship' for him to take north. Written from Maranham [Maranhao, Brazil]
This letter is referred to in Sabine's published work 'An Account of Experiments to Determine the Figure of the Earth', 1825
He last wrote to Davy from the Gambia, and hopes that Mr Browne [Henry Browne, husband of Sabine's sister Caroline] has been updating him on his progress and welfare since, and that the enclosures he has sent via Browne excuse the intermission in his correspondence; he has been completing on-the-spot abstracts of the principal observations he has made at each station, which is especially useful in Africa, where the risk of death adds extra importance to immediate note-taking; he hopes that Davy approves of his diligence; the move to the HMS Pheasant has extended his opportunities greatly; Clavering [Douglas Charles Clavering, captain of HMS Pheasant] has paid great attention to landing and re-embarking his instruments, and there have been no accidents so far; he took a second invariable pendulum as a precautionary measure, and has employed both instruments and obtained a double series of experiments at each station; the clock with the two solid pendulums, which he had with him on Parry's 1819 Arctic voyage [William Edward Parry, arctic explorer; Sabine accompanied Parry on his 1819 expedition], runs well and produces results that match those of the detached pendulums; the clock must have a fair trial due to the importance of corresponding results by different methods; the pendulum stations set up so far have been Sierra Leone at latitude 8°29'N, St Thomas's [Sao Tome, Sao Tome and Principe], 25 miles north of the equator, Ascension [Ascension Island, British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha] at 7°56'S, Bahia [Brazil] at 12°59'S and Maranham [Maranhao, Brazil] at 2°31'S; this makes four stations within 10° of the equator, and one a little beyond; Clavering intends to give him the opportunity to set up stations at Trinidad for the parallel of 10°, at Jamaica for 20°, at Bermuda for 30°, and at the Azores [Portugal] for 40°; London will suffice for a station near enough to the 50th degree; the purpose of this letter is to request an extension of the experiments towards the north in the summer of the following year; irregularities of local attraction in the superficial geological strata may exist but do not show any obvious external manifestation, thus sites cannot be chosen with regard to them, and the pendulum itself may be the only means of discovering them; these irregularities are the main difficulty in determining the figure of the earth, and the most probable method of removing their influence from his -data is simply to set up experiments in 'every diversity of circumstance' in order to neutralise it on the final result, with the only necessary constant being that they are all as close to sea level as possible; as such, the selection of locations for further experiments could be decided based on general convenience; he proposes that future stations could be a northern Scottish island for the 60° parallel, the south cape of Norway for the 70° parallel, and Spitsbergen [Svalbard, Norway] and a second location on the east coast of Greenland for the 80° parallel, as well as a fifth in Iceland at latitude 64; these experiments may be carried out easily if undertaken in that order; the Admiralty have proven their readiness to aid in his experiments and should provide a means of conveyance for the proposed future experiments; he thinks that the voyage could be of service to geographical knowledge, as the eastern coast of Spitsbergen and the eastern coast of Greenland above 72° have rarely been visited; a channel opens in the ice during the summer months, due to the tides and heat absorption by nearby land, through which they can pass to access lesser-known parts of the Greenland coast further north; the only voyage recorded to these areas is that of Hudson [Henry Hudson, 17th-century explorer and navigator] who reached 82°N, but the account is imperfect [Hudson actually reached 79°49'N, and thought that Svalbard's northernmost point that they could see was 82°N, but it was in fact 80°49'N]; the majority of people believe Hudson's tales to be false, but he considers him to be one of the navigators of that period in discovery who was discredited at the time but was justified in the end, and of whom we should be proud [Hudson's crew mutinied and set him adrift in Hudson Bay; his version of events from his last voyage was never heard]; if the shores of Greenland extend sufficiently northward, a passage should open in the ice to a higher latitude than they would ever be able to reach in the open ocean; this theory is supported with evidence from all previous expeditions to the Arctic Circle, in which passage has only been found close to land; they will only need to take one ship to the east coast of Greenland, rather than two as on northwest discovery voyages, as in the event of the vessel's loss they can take boats safely down the coast to Iceland; geographical exploration should come second to the pendulum experiments, as they must be undertaken by the same observer with the same instrument and without delay; he is concerned that if there is any restriction in time, it will be allotted based on the interests of the commander of the voyage rather than for its main purpose, and as such he requests that Clavering lead the northern voyage the following year as he is accustomed to aiding with the experiments [Clavering was in fact chosen to lead the expedition to Greenland and Norway on the HMS Griper in 1823]; he is very willing in turn to aid Clavering in his own maritime investigations, as the 'intimacy and confidence' they have would 'render such cooperation mutually agreeable', and he is familiar with northern navigation from his 1819 voyage with Captain Parry; he apologises for the long letter, but had he waited until seeing Davy in person the voyage would have been delayed until the summer of 1824, and he hopes to avoid postponing any part of the experiments; they will not arrive back in England before the middle of January, and he hopes to sail earlier in the spring than northern voyages usually do in order to reach Spitsbergen as early in the season as it is accessible, once the experiments in the 60th and 70th parallels are complete; he has enclosed an account of Breguet's [Abraham-Louis Breguet, Swiss horologist] chronometer between February and August as a continuation of the report he sent from the Gambia; he requests that a copy be sent to Breguet, as he may wish to replace the chronometer 'by one better prepared to enter in competition with British workmanship' for him to take north
Extent - 6 page letter (2 sheets)
Repository - Royal Horticultural Society Lindley Library
Copyright - John J. Timothy Jeal
Credit Line - Courtesy John J. Timothy Jeal / RHS Lindley Collections
Usage terms - Non-commercial use with attribution permitted (CC BY-NC 4.0)