. Appendix to Captain Parry's journal of a second voyage [microform] : for the discovery of a north-west passage from the Atlantic to the Pacific, performed in His Majesty's ships Fury and Hecla in the years 1821-22-23. Science; Botany; Sciences; Botanique. 261 ON THE FREEZING POINT OF DISTILLED MERCURY. THE AMALGAMS, ^c. To determine tlie freezing point of pure mercury; a portion of it was put into a shallow glass evaporating dish, and placed u|)on a support consisting of a slender rim of copper, with three glass legs. The bulbs of two spirit thermometers were -placed upon each side of the di
. Appendix to Captain Parry's journal of a second voyage [microform] : for the discovery of a north-west passage from the Atlantic to the Pacific, performed in His Majesty's ships Fury and Hecla in the years 1821-22-23. Science; Botany; Sciences; Botanique. 261 ON THE FREEZING POINT OF DISTILLED MERCURY. THE AMALGAMS, ^c. To determine tlie freezing point of pure mercury; a portion of it was put into a shallow glass evaporating dish, and placed u|)on a support consisting of a slender rim of copper, with three glass legs. The bulbs of two spirit thermometers were -placed upon each side of the dish, and the bulb of another in the centre of the mercury, the thormnmcfer iM'.ing attached to the stand, and in a vertical position. These thermometers had each been compared frequently with the standard mercurial one, when the temperature was not lower than -30" Fahrenheit, and their respective errors applied at lower temperatures. The great ditt'erence between spirit thermometers at very low temperatures, renders any dependancc upon them, when accuracy is required, very precarious, without a comparison with the mercurial ones, a few degrees above the freezing point of mercury. Among eighteen spirit thermometers, frequently comjiared nearly at the same time, there was a difference often amounting to twenty degrees at temperatures between 40" and 50" below Zero; and to show how much this was the case even in those made by the same maker and of the same length and construction, the following is a comparison of ten of them. They were placed in parallel and vertical positions, upon a board fixed to two upright supports about three feet above the frozen sea, and each of them was freely suspended at the end of a nail. The temperature at the time of comparison had been very steady for a considerable time. No. 1. . .. - .'.«* lahr. - 50 11 - 40 â¢1 ' Meftn - 6*°.4 Fahr. -49 t« - 5)1 11 -40 It - 40 i« -44 11 Mean - i^.% Fahr - 44 If 10 -46 II ((â oloured).
Size: 922px × 2711px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectbotany, booksubjectscience, bookyear1
