Of WATER by HEAT:. 393 



warmer water. The legitimate inference from this is, that wa- 

 ter of temperature 40 ° is not contracted by being cooled to 



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- 

 feflion 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 infe- 

 rior thermometer, or to atteft the contraction of water by cold. 



This experiment, however, I muft remark, does not warrant 

 the conclufion, that the water is actually expanded, though it in 

 no degree oppofes it. It proves no more, than that the contrac- 

 tion ceafes at 40 ° ; and that water of 32 ° is not more denfe than 

 of 39 or 40 °. Nay, fome may perchance allege, that it does 

 not prove fo much ; conceiving, that if at 40 the contraction, 

 without ceafing altogether, becomes very inconfiderable, the dif- 

 ference of denfity occafioned by the fubfequent reduction of 

 temperature may be fo very trifling, as not to enable the cold 

 particles to take that fituation which their gravity afligns to 

 them, in oppofition to the inertia and tenacity of the fubjacent 

 mafs j and therefore that the colder, though heavier fluid, may 

 he conftrained to remain above. That this allegation fliould 

 have no weight attached to it, the circumflances of the fucceed- 

 ing experiment will clearly fhow, as I fhall foon notice. 



Before quitting the consideration of the prefent experiment, 

 it may be worth while to remark, that it may feem rather fur- 

 prifing, that the bottom of the fluid was not apparently affected 

 in its temperature by the ice which fo long occupied its furface. 

 It might be expected, though no cold currents defcended from 

 above, that the caloric fhould be conducted from below, and 



3 E 2 that 



