DILATATTON OF THE CASKS. Q6\ 



inuft be added that of a cylinder of water terminated at one 

 end by the line of the ftation of the mercury, and at the other 

 by the neck of the receiver. 



I might add a few more details, but I (hall fupprefs them 

 for the fake of brevity, and beeaufe per fons very little accuf- 

 tomed to manipulation will eafily fupply the defect. 



However, as it is important, from what I have already 

 faid to exclude water entirely from the. apparatus, I (hall 

 mention how I fucceeded in completely effecling this pur- 



r 



pole. 



If the receiver was vifibly moift, I firft dried it with blotting Methods of ex- 

 paper, and then heated it fo as to evaporate part of the water c ^ dlt l g m °'/~ 

 it might ftill contain, and by means of bellows, to which Ig as . 

 adjufled a glafs tube, I expelled the vapour by a current of 

 air. Thefe laft operations being repeated feveral times on 

 the receiver and tube, both were found perfectly dry. The , 



mercury which I ufed in my experiments was always em- 

 ployed very dry and pure. 



In all the experiments, the refults of which I am about to The terms of 



give, I always reduced the gafes (the dilatation of which g™%JhSC in 



could be determined by the apparatus here defcribed) to the experiments 



temperature of melting ice. For this purpofe I had a bath we , r< ; ^ ezm 5 ~ 

 ...... ,. , , • i 11 • r i and boiling wa-., 



with ice in it, into which the receiver was wholly immerled, ter# 



after having withdrawn it from the bath where it was placed 

 for the experiment, and was left there for about half an hour, 

 during which I often ftirred the ice. The other fixed tempe- 

 rature, at which I refted for the fame gafes, was that of boil- 

 ing water. 



I made fome experiments at other temperatures ; but they Experiments at 



require to be again repeated, and will befides form a part of other tem P era * 

 * ,,..,. T tures require to 



a work I have begun on the law of the dilatation of gafes and be repeated. 



vapors. I (hall therefore confine myfelf to the dilatation of 

 gafes at a fixed elevation of temperature, which (lia.ll be that 

 comprifed between the degree of melting ice and the boiling 

 point. With regard to the vapors, I (hall compare their dila- 

 tation with that of the gales. 



Art. IV. Experiments and Refults. 



When I ufed the two apparatufes here defcribed, but of- Expanfion from 



fcener the fecond than the firft, and avoiding all the caufes off reezing t0 boil_ 



° . ing water, 



uncertainty 



