2 52 7 W>. Cavendish’s Account of fame 
part; as it was found, in the undiluted acid, that the latter con- 
fined of a Wronger, and confequently heavier, acid than the 
former. But ftill the fubfidence of the frozen part fhews, that 
the ice is not mere water, or even a very dilute acid; which 
indeed was proved by the examination of the liquors fent 
home. 
The ninth and tenth articles fhew, that though the acids 
bear being cooled greatly below the freezing point, without 
any congelation taking place, yet as foon as they begin to 
freeze they immediately rife up to their freezing point ; and 
this point is always very nearly, if not exactly, the fame in the 
fame acid ; for thofe acids were frozen and melted again three 
or four times, and were cooled confiderably more below the 
freezing point in one trial than another, and yet as foon as 
they began to freeze the thermometer immerfed in them con- 
ftantly rofe nearly to the fame point. 
The quantity which thefe acids will bear being cooled below 
the freezing point, without freezing, is remarkable. The 
diluted fpirit of nitre, whofe freezing point is — i°|, once bore 
being cooled to near — 39 0 , without freezing, that is, near 37 
degrees below its freezing point. The diluted dephlogifticated 
fpirit of nitre, whofe freezing point is — 5 0 , bore cooling to - 35 0 ; 
and the dephlogifticated fpirit of nitre (141) whofe true freezing 
point is moft likely — 19 0 ( fee next article ) bore being cooled to 
— 49 0 : perhaps too they might have born to be cooled confi- 
derably lower without freezing, but how much does not appear. 
It muft be obferved, however, that the fame diluted fpirit 
which at one time bore being cooled to — 39 0 , at another froze, 
without any apparent caufe, when its cold was certainly lefs 
than — -30% and moft likely not much below ~ 18°. 
4 12 * 
