350 ,eoNTRACTron or water by heat, 



half inches diftant from the cooling power. No one car* en- 

 tertain a doubt that this is owing to a current of cooled and con- 

 denfed fluid defcending, and a correfponding one of a warmer 

 temperature afcending. Now, if water obferved the fame 

 law that other bodies do, and had no peculiarity of conftitu- 

 tion, the fame progrefs of cooling (hould continue. This, how- 

 ever, the experiment teaches us, is not the cafe: as foon as 

 the fluid at the bottom exhibits a temperature of 40°, it 

 ceafes. The colder fluid remains at top, and quickly lofing 

 4s the fluid be- temperature, ere long begins to freeze. The continuance of 

 nuedat top" it" ^ e c0 ^ er ^ u ^ at tr, e furface furely denotes, that it is not 

 *na not denfer more denfe than thefubjacent warmer water. The legitimate 

 thanthatat ^' inference from this is, that water of temperature 40° is not 

 contracted by being cooled to 32°. 



Did water obferve the ufual law, and lofe volume along with 

 temperature, this experiment, by its long duration, afforded 

 ample time for the manifeftation of it. 



For not lefs than two days did ice-cold water maintain pof- 

 feffion of the top, and for the fame period the temperature at 

 the bottom never fell below 39°. No current, therefore, of 

 cold and condenfed fluid moved from the furface, to affect the 

 inferior thermometer, or to atteft the contraction of water 

 by cold. 

 Yet the experi- This experiment, however, I muft remark, does not warrant 



rnent does not the conc i u f lon that the water is actually expanded, though it 

 ihow that it was . g J t b 



rarer, ln no. degree oppoies it. It proves no more, than that the 



contraction ceafes at 40° ; and that water of 32° is not more 

 It might be even denfc than of 39° or 40°. Nay, fome may perchance alledge, 

 alledgcd that a that it does not prove fo much ; conceiving, that if at 40° the 

 denfity pre- contraction, without ceafing altogether, becomes very incon- 

 vailedj fiderable, the difference of denfity occafioned by the fubfe- 



quent reduction of temperature may be fo very trifling, as not 

 to enable the cold particles to take that fituation which their 

 gravity affigns to them, in oppolition to the inertia and tena- 

 city of the fubjacent mafs ; and therefore that the colder, 

 though heavier fluid, may be conftrained to remain above, 

 but this is not That this allegation mould have no weight attached to it, the 

 entitled to re- circum (lances of the fucceeding experiment will clearly iliow, 



as I (hall foon notice, 

 Thathtatwhich Before quitting the confideration of the prefent experiment, 



paiTed by dire<3 it m ^ wurLn wn j| e to jemark, that it may feem rather fu.r- 



communicatioa * * . r 



pnfing, 



