Copy letter from Edward Sabine [to Humphry Davy, chemist and inventor, president of the Royal Society]
Information
Title - Copy letter from Edward Sabine [to Humphry Davy, chemist and inventor, president of the Royal Society]
Record type - Archive
Original Reference - RHS/Col/2/Z1/10
Date - 29 Jan 1822-2 Feb 1822
Scope & content - Written from HMS Iphigenia between the Cape Verde Islands and Goree [Goree, Senegal]
Part of the letter was published in 'The Quarterly Journal of Science, Literature, and Art', 1823, Volume 15, pages 75-82 ('An account of a barometrical measurement of the height of the Pico Ruivo, in the island of Madeira. Extracted from a letter written by Captain Edward Sabine, of the Royal Artillery, to Sir Humphry Davy, Bart, President of the Royal Society, dated in January, 1822, on board His Majesty's Ship Iphigenia, on passage between the Cape Verd Islands and Goree')
Letter started on 29 Jan 1822
They could not sail until 4 Jan from Plymouth due to poor winds in the Channel; this loss of six weeks will abridge their stays at the various islands en route to Africa; they could have used the time to employ members more agreeably and profitably than was possible in the Channel [English Channel] and the Bay of Biscay; they anchored in Funchal Bay [Madeira, Portugal] on Friday 11 Jan and sailed on Tuesday 15 Jan, though they would have loved to prolong their stay since they were most kindly received and the climate was good; they admired the plants growing in Madeira, where the climate is so much better than in England, only five days' sail away; it would be desirable to be able to create different climates artificially to enable the collection of vegetation worldwide; the mountainous interior of Madeira has been made more accessible by new roads passable on mules or the local small horses, and he travelled to the highest summit, Pico Ruivo [Madeira], to measure its height with Mr Newman's [John Frederick Newman, instrument maker in London] portable barometer with iron cistern; he was accompanied by Captain Clavering [Douglas Charles Clavering] of the HMS Pheasant, Mr Whitelaw [Robert Whitelaw] the surgeon of the Iphigenia, George Don, two midshipmen and Mr Blackburne [Henry Blackburn], an English merchant resident at Madeira; Blackburne had ascended previously and led the party, aided by his local knowledge and ability to communicate with the local guides and attendants; Lieutenant Stokes [Pringle Stokes] of the Iphigenia remained on board to note variations in temperature and density of the atmosphere, and of the point of deposition indicated by Mr Daniell's [John Frederic Daniell, chemist and physicist, friend of Edward's at the Royal Society] hygrometer; these variations were measured hourly so as to be simultaneous with those made by the party on Pico Ruivo; the results of these observations are enclosed on a separate sheet; they left Funchal before dawn and travelled six miles to Camera de Loubos [Camara de Lobos, Madeira], and then ascended to the north; they ate breakfast at the Jardim de Serra, a house which Mr Veitch [Henry Veitch, British consul in Madeira] built at an elevation of nearly 2,700 feet; the vegetation approaching this height reminded them of English vegetation; the people of Madeira, on their way to mass, were courteous, in good health, well clothed, and the men able-bodied and good-looking, though the women were 'almost without exception' very plain; the temperature at Jardim de Serra was 16 degrees lower than at Funchal, lower than expected; the first sight of the Curral [Curral das Freiras, Madeira] was half an hour's ascent from the Jardim, and was the most magnificent view he had ever seen, being unaccustomed to mountains; the Curral das Freiras is a ravine several miles long and over 4,000 feet in altitude, partly forested by laurels (nobilis [Laurus nobilis], indica [Persea indica] and foetens [Ocotea foetens]) and partly exposed; the valley contains a small yet fierce river; their route passed over an elevated and snowy ridge in order to descend into the Curral, where there is a spring forming a pool, the water at 47 degrees and air at 46 degrees at an elevation of 4,454 feet; at this point the summit of Pico Ruivo was clear of clouds for some minutes, and this was the only period in which the moisture levels in the air were lower than Funchal; the easterly winds were light and pleasant; to save time, their Portuguese attendant led the horses into the valley whilst the party descended on foot, stopping to admire the scenery; at noon they crossed the river on a fallen tree and followed a road to the head of the valley where they began to ascend again, passing through brooms and ferns; at 2pm they reached the highest point attainable on horseback due to snow depth and road breaches, which was a ridge 4,380 feet above sea level; he and Whitelaw continued on foot, while the others returned to the valley; they climbed for an hour and a half through a thick evergreen forest consisting of laurels, Quercus ilex and Erica arborea, enveloped in clouds and walking through thick snow, to the summit; their only inconvenience was being wet from the rain and a little cold while they measured the height of the peak; they were unable to enjoy the views due to the clouds; he measured the height as 5,430 feet and 2 inches, using Dr Hutton's [Charles Hutton, mathematician] method of computation, being most familiar with it; by deducting the pressure due to water vapour in the atmosphere from the barometric heights, the elevation would measure 5,236 feet and 2 inches; he gives two results for each station, not having seen this correction of the barometric heights applied in practice elsewhere; it was dark when they rejoined their party in the valley, and they took a precipitous ascent on horseback by torchlight on the opposite side of the Curral to take a more direct road to Funchal, which they reached safely by midnight; the barometer functioned extremely well in both conveyance and use, as long as the cistern was held upright, and the iron cistern had many advantages over those of leather or wood, including protection from damp and freedom of the mercury from air and moisture, ensuring more certain results; he regrets he could not use it ascending the Peak of Tenerife [Pico del Teide] as they were only able to remain seven hours at Santa Cruz due to their delayed departure from England; it is said that both peaks are inaccessible in the winter season, but he believes that they simply require more exertion than is usually required of travellers, as Captain Baudin [Nicholas Thomas Baudin, French explorer] succeeded in December; he believes that it is worth determining the height of this peak by barometer, which could also produce important meteorological and other results, helping to determine the variation in barometric results due to varying atmospheric conditions and a comparison of the two modes of measurement (geometrically with modern instruments and barometrically), requiring several hours' stay near the summit, repeating the observations at intervals with multiple instruments; he is also disappointed to have only briefly passed by Fuego [Fogo, Cape Verde], as there has been no good account published of this 'very remarkable' island; the peak of Fuego rises almost in a cone from the water's edge to a height higher than that of San Antonio [Santo Antao, Cape Verde], which was estimated by Captain Horsburg [James Horsburgh, Scottish hydrographer] to be 7,400 feet; the peak was visible from the ship for two days, and although volcanic, remained clear at that time; he believes Fuego to be an eligible station for experiments on the relations of heat and moisture to the atmosphere; the second of the appendices contains observations on the magnetic dip, variation, and force; the rate of the variation of the force did not conform with Dr Young's [Thomas Young, scientist] formula very well, but it may have been a result of interferences due to the volcanic nature of the islands; the results were nevertheless satisfactory, especially in the agreement of the different needles; if the needles continue to agree, he can continue the experiment, collecting a body of results at various stations during the voyage; the third of the appendices contains an account of Breguet's [Abraham-Louis Breguet, Swiss horologist in France] chronometer, belonging to the Commissioners of Longitude [Commissioners for the Discovery of the Longitude at Sea, or Board of Longitude, a British government body formed to encourage solving the problem of finding longitude at sea] with observations from Feb 1821 to Jan 1822; the rate of the chronometer on the Iphigenia was reduced by comparison with those of Parkinson and Frodsham [William Parkinson and William James Frodsham, horologists], which function with great uniformity on board ships; otherwise Breguet's chronometer functions well, and the fault can easily be remedied, although at present it is of no practical value; he will continue observing its functioning on the return journey; all current directories and other works state the longitude and latitude of a location generally, rather than in reference to a particular local point, leading to inaccuracies and preventing accurate comparison of chronometers with correct Greenwich time by navigators; an inaccuracy resulting in the loss of a second per day will, over a long journey, be multiplied, and therefore without more precision, giving the time in seconds is 'absurd'; he had hoped to determine the precise location of one spot in Funchal by lunar observations, but required another day for this to be possible; the consul's house would be an eligible location for observations, being frequented by naval officers and ship masters, and with a good view of the sea horizon from a turret, helpful for masters of merchant ships in particular, who may not always be familiar with or possess an artificial horizon; the few hours spent at Santa Cruz [Tenerife] were cloudy, preventing comparison with Humboldt's [Alexander von Humboldt, Prussian geographer, naturalist and explorer] longitude; on 26 Jan he measured, comparing the chronometers, the location of the watering place at Porto Praya [Praia, Santiago, Cape Verde] as 23°31'10'', while works such as the 'Connaissance des temps' [French annual publication of astronomical ephemerides] and Lax [William Lax, astronomer and mathematician] differ from this
Letter continued, written from the entrance to the Gambia, 2 Feb 1822
He has found an unexpected opportunity to send letters to England from St Mary's [Banjul, the Gambia] by a merchant brig; he will write again from Sierra Leone on other subjects, especially those to which Davy [Humphry Davy, chemist and inventor, president of the Royal Society] has directed his attention; Sir Robert Mends [captain of HMS Iphigenia] is attentive but very pressed for time; he has put the packet under Mr Barrow's [John Barrow, second secretary to the Admiralty, fellow of the Royal Society] name to ensure its safety
Enclosed are three pages of observations. Number 1, 'Observations made at Madeira, January 13th 1822, to determine the elevation of several stations in the ascent to the Pico Ruivo', comprises two tables, the first detailing variations in temperature, air pressure and the point of deposition by Daniell's hygrometer, on board the Iphigenia in Funchal Bay, comparing two barometers; the second table details observations made ascending Pico Ruivo, from Jardim de Serra, at the upper story of Veitch's house, at the basin of the spring, at a crossroads, at the summit and below the summit, with the results corrected to reflect the variations caused by the cistern and air density in Madeira
Number 2, 'Magnetic observations', comprises three tables: the first details the magnetic dip, measured using Meyer's needle in Madeira (in Veitch's garden), Tenerife (in Santa Cruz, on the beach east of the town and St Jago (in Porto Praya, at the watering place east of the town); the second table details the 'intensity of the force, with the needles suspended horizontally', in London, Madeira, Tenerife and St Jago; the third table details the variation in Madeira, Tenerife and St Jago
Number 3, 'An account of the going of Breguet's chronometer No 3194, the property of the Commissioners of Longitude, from February 1821 to January 1822', detailing the rate of the chronometer and temperature. Written from HMS Iphigenia between the Cape Verde Islands and Goree [Goree, Senegal]
Part of the letter was published in 'The Quarterly Journal of Science, Literature, and Art', 1823, Volume 15, pages 75-82 ('An account of a barometrical measurement of the height of the Pico Ruivo, in the island of Madeira. Extracted from a letter written by Captain Edward Sabine, of the Royal Artillery, to Sir Humphry Davy, Bart, President of the Royal Society, dated in January, 1822, on board His Majesty's Ship Iphigenia, on passage between the Cape Verd Islands and Goree')
Letter started on 29 Jan 1822
They could not sail until 4 Jan from Plymouth due to poor winds in the Channel; this loss of six weeks will abridge their stays at the various islands en route to Africa; they could have used the time to employ members more agreeably and profitably than was possible in the Channel [English Channel] and the Bay of Biscay; they anchored in Funchal Bay [Madeira, Portugal] on Friday 11 Jan and sailed on Tuesday 15 Jan, though they would have loved to prolong their stay since they were most kindly received and the climate was good; they admired the plants growing in Madeira, where the climate is so much better than in England, only five days' sail away; it would be desirable to be able to create different climates artificially to enable the collection of vegetation worldwide; the mountainous interior of Madeira has been made more accessible by new roads passable on mules or the local small horses, and he travelled to the highest summit, Pico Ruivo [Madeira], to measure its height with Mr Newman's [John Frederick Newman, instrument maker in London] portable barometer with iron cistern; he was accompanied by Captain Clavering [Douglas Charles Clavering] of the HMS Pheasant, Mr Whitelaw [Robert Whitelaw] the surgeon of the Iphigenia, George Don, two midshipmen and Mr Blackburne [Henry Blackburn], an English merchant resident at Madeira; Blackburne had ascended previously and led the party, aided by his local knowledge and ability to communicate with the local guides and attendants; Lieutenant Stokes [Pringle Stokes] of the Iphigenia remained on board to note variations in temperature and density of the atmosphere, and of the point of deposition indicated by Mr Daniell's [John Frederic Daniell, chemist and physicist, friend of Edward's at the Royal Society] hygrometer; these variations were measured hourly so as to be simultaneous with those made by the party on Pico Ruivo; the results of these observations are enclosed on a separate sheet; they left Funchal before dawn and travelled six miles to Camera de Loubos [Camara de Lobos, Madeira], and then ascended to the north; they ate breakfast at the Jardim de Serra, a house which Mr Veitch [Henry Veitch, British consul in Madeira] built at an elevation of nearly 2,700 feet; the vegetation approaching this height reminded them of English vegetation; the people of Madeira, on their way to mass, were courteous, in good health, well clothed, and the men able-bodied and good-looking, though the women were 'almost without exception' very plain; the temperature at Jardim de Serra was 16 degrees lower than at Funchal, lower than expected; the first sight of the Curral [Curral das Freiras, Madeira] was half an hour's ascent from the Jardim, and was the most magnificent view he had ever seen, being unaccustomed to mountains; the Curral das Freiras is a ravine several miles long and over 4,000 feet in altitude, partly forested by laurels (nobilis [Laurus nobilis], indica [Persea indica] and foetens [Ocotea foetens]) and partly exposed; the valley contains a small yet fierce river; their route passed over an elevated and snowy ridge in order to descend into the Curral, where there is a spring forming a pool, the water at 47 degrees and air at 46 degrees at an elevation of 4,454 feet; at this point the summit of Pico Ruivo was clear of clouds for some minutes, and this was the only period in which the moisture levels in the air were lower than Funchal; the easterly winds were light and pleasant; to save time, their Portuguese attendant led the horses into the valley whilst the party descended on foot, stopping to admire the scenery; at noon they crossed the river on a fallen tree and followed a road to the head of the valley where they began to ascend again, passing through brooms and ferns; at 2pm they reached the highest point attainable on horseback due to snow depth and road breaches, which was a ridge 4,380 feet above sea level; he and Whitelaw continued on foot, while the others returned to the valley; they climbed for an hour and a half through a thick evergreen forest consisting of laurels, Quercus ilex and Erica arborea, enveloped in clouds and walking through thick snow, to the summit; their only inconvenience was being wet from the rain and a little cold while they measured the height of the peak; they were unable to enjoy the views due to the clouds; he measured the height as 5,430 feet and 2 inches, using Dr Hutton's [Charles Hutton, mathematician] method of computation, being most familiar with it; by deducting the pressure due to water vapour in the atmosphere from the barometric heights, the elevation would measure 5,236 feet and 2 inches; he gives two results for each station, not having seen this correction of the barometric heights applied in practice elsewhere; it was dark when they rejoined their party in the valley, and they took a precipitous ascent on horseback by torchlight on the opposite side of the Curral to take a more direct road to Funchal, which they reached safely by midnight; the barometer functioned extremely well in both conveyance and use, as long as the cistern was held upright, and the iron cistern had many advantages over those of leather or wood, including protection from damp and freedom of the mercury from air and moisture, ensuring more certain results; he regrets he could not use it ascending the Peak of Tenerife [Pico del Teide] as they were only able to remain seven hours at Santa Cruz due to their delayed departure from England; it is said that both peaks are inaccessible in the winter season, but he believes that they simply require more exertion than is usually required of travellers, as Captain Baudin [Nicholas Thomas Baudin, French explorer] succeeded in December; he believes that it is worth determining the height of this peak by barometer, which could also produce important meteorological and other results, helping to determine the variation in barometric results due to varying atmospheric conditions and a comparison of the two modes of measurement (geometrically with modern instruments and barometrically), requiring several hours' stay near the summit, repeating the observations at intervals with multiple instruments; he is also disappointed to have only briefly passed by Fuego [Fogo, Cape Verde], as there has been no good account published of this 'very remarkable' island; the peak of Fuego rises almost in a cone from the water's edge to a height higher than that of San Antonio [Santo Antao, Cape Verde], which was estimated by Captain Horsburg [James Horsburgh, Scottish hydrographer] to be 7,400 feet; the peak was visible from the ship for two days, and although volcanic, remained clear at that time; he believes Fuego to be an eligible station for experiments on the relations of heat and moisture to the atmosphere; the second of the appendices contains observations on the magnetic dip, variation, and force; the rate of the variation of the force did not conform with Dr Young's [Thomas Young, scientist] formula very well, but it may have been a result of interferences due to the volcanic nature of the islands; the results were nevertheless satisfactory, especially in the agreement of the different needles; if the needles continue to agree, he can continue the experiment, collecting a body of results at various stations during the voyage; the third of the appendices contains an account of Breguet's [Abraham-Louis Breguet, Swiss horologist in France] chronometer, belonging to the Commissioners of Longitude [Commissioners for the Discovery of the Longitude at Sea, or Board of Longitude, a British government body formed to encourage solving the problem of finding longitude at sea] with observations from Feb 1821 to Jan 1822; the rate of the chronometer on the Iphigenia was reduced by comparison with those of Parkinson and Frodsham [William Parkinson and William James Frodsham, horologists], which function with great uniformity on board ships; otherwise Breguet's chronometer functions well, and the fault can easily be remedied, although at present it is of no practical value; he will continue observing its functioning on the return journey; all current directories and other works state the longitude and latitude of a location generally, rather than in reference to a particular local point, leading to inaccuracies and preventing accurate comparison of chronometers with correct Greenwich time by navigators; an inaccuracy resulting in the loss of a second per day will, over a long journey, be multiplied, and therefore without more precision, giving the time in seconds is 'absurd'; he had hoped to determine the precise location of one spot in Funchal by lunar observations, but required another day for this to be possible; the consul's house would be an eligible location for observations, being frequented by naval officers and ship masters, and with a good view of the sea horizon from a turret, helpful for masters of merchant ships in particular, who may not always be familiar with or possess an artificial horizon; the few hours spent at Santa Cruz [Tenerife] were cloudy, preventing comparison with Humboldt's [Alexander von Humboldt, Prussian geographer, naturalist and explorer] longitude; on 26 Jan he measured, comparing the chronometers, the location of the watering place at Porto Praya [Praia, Santiago, Cape Verde] as 23°31'10'', while works such as the 'Connaissance des temps' [French annual publication of astronomical ephemerides] and Lax [William Lax, astronomer and mathematician] differ from this
Letter continued, written from the entrance to the Gambia, 2 Feb 1822
He has found an unexpected opportunity to send letters to England from St Mary's [Banjul, the Gambia] by a merchant brig; he will write again from Sierra Leone on other subjects, especially those to which Davy [Humphry Davy, chemist and inventor, president of the Royal Society] has directed his attention; Sir Robert Mends [captain of HMS Iphigenia] is attentive but very pressed for time; he has put the packet under Mr Barrow's [John Barrow, second secretary to the Admiralty, fellow of the Royal Society] name to ensure its safety
Enclosed are three pages of observations. Number 1, 'Observations made at Madeira, January 13th 1822, to determine the elevation of several stations in the ascent to the Pico Ruivo', comprises two tables, the first detailing variations in temperature, air pressure and the point of deposition by Daniell's hygrometer, on board the Iphigenia in Funchal Bay, comparing two barometers; the second table details observations made ascending Pico Ruivo, from Jardim de Serra, at the upper story of Veitch's house, at the basin of the spring, at a crossroads, at the summit and below the summit, with the results corrected to reflect the variations caused by the cistern and air density in Madeira
Number 2, 'Magnetic observations', comprises three tables: the first details the magnetic dip, measured using Meyer's needle in Madeira (in Veitch's garden), Tenerife (in Santa Cruz, on the beach east of the town and St Jago (in Porto Praya, at the watering place east of the town); the second table details the 'intensity of the force, with the needles suspended horizontally', in London, Madeira, Tenerife and St Jago; the third table details the variation in Madeira, Tenerife and St Jago
Number 3, 'An account of the going of Breguet's chronometer No 3194, the property of the Commissioners of Longitude, from February 1821 to January 1822', detailing the rate of the chronometer and temperature
Extent - 14 page letter (5 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)