A voyage towards the North Pole : undertaken by His Majesty's command, 1773 . ntain above A was found > - . 1439,8 feet: Deprefllon of C feen from A was i 54; Z a Hence 151 152 the height of A above C is - 58,7 feet; Height of the mountain above C 1498,5 feet: + height of C above waters edge - 5 ; Height of mountain above the level of the fea 1503,5 feet;which differs from that found by the fingle angle threetenths of a foot. I cannot account for the great difference between thegeometrical meafure and the barometrical one accordingto M. De Lucs calculation, which amounts to 8
A voyage towards the North Pole : undertaken by His Majesty's command, 1773 . ntain above A was found > - . 1439,8 feet: Deprefllon of C feen from A was i 54; Z a Hence 151 152 the height of A above C is - 58,7 feet; Height of the mountain above C 1498,5 feet: + height of C above waters edge - 5 ; Height of mountain above the level of the fea 1503,5 feet;which differs from that found by the fingle angle threetenths of a foot. I cannot account for the great difference between thegeometrical meafure and the barometrical one accordingto M. De Lucs calculation, which amounts to 84,7 have no reafon to doubt the accuracy of Dr. Irvings ob-fervations, which were taken with great care. As to thegeometrical meafure, the agreement of fo many triangles,each of which muft have deteded even the fmallefT the moft fatisfaftory proof of its corrednefs. Since myreturn, I have tried both the theodolite and barometer,to difcover whether there was any fault in either, and findthem upon trial, as I had always done before, veryaccurate. Observations. APPENDIX. 153 Observations for determining the Acceleration of the Pendulum. Defcription of the Pendulum with which the Obfervationswere made, by Mr. Gumming. ^T~^HE apparatus with which the following experi-ments were made, was prepared for the voyage with all the care which the (hortnefs of the time would admit, and particular attention was paid to its fimplicity. The pendulum was that which the late Mr. George Graham had conftrufted, to afcertain the exad diftance between the center of motion and center of ofcillation of a pendulum to vibrate feconds at London. The ball is a fphere of folid brafs, whofe diameter is three inches and ninety two hundredth parts of an inch ; and whofe weight is nine pounds and one quarter. The rod is a round fteel wire, one tenth of an inch thick, and is fo firmly fcrewed into the ball, that h cannot be unfcrewed by hand, nor the length of the pendulum altered without the app
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