Essays and observations on the construction and graduation of thermometers, and on the heating and cooling of bodies / By George Martine.

George Martine

Date:: 1772

Credit: Essays and observations on the construction and graduation of thermometers, and on the heating and cooling of bodies / By George Martine. Source: Wellcome Collection.

79/192 (page 69)

$The Thermometer in the little bow] was fome- what above gr. 112 in the beginning; which was the caufe of the times of the falling to fuch and fuch degrees of heat to be always about a minute longer than the theory required. ‘There was fome-_ thing though lefs of this too in the forgoing expe- riment. And making a due allowance for thefe fmatl and truly inconfiderable variations the theory coincides furprifingly with obfervation : nearer in- deed than we could well expec in fuch experiments, -whercia the inftruments mult be allowed not to come up to a mathematical exactnels. A very {inall and infenfible error in the conftruction of the Thermometers, or a very inconfiderable miftake, “as of about a quarter or half a degree in making the obfervation, would feemingly occafion a very fenfible diference between the time actually obfer- ved and that which the theory required. To try ic in bodies differing ftill more in bulk from one another, the heat of the air being gr. 48, there were two vefiels filled, the one with one gill - and the other with 27 gills of water; their refpec- tive diameters thus being 1 and 3; and the refri- | gerations came out in this order. Degrees$