MINIMUM TEMPERATURE OF V.'ATER, Jpl 



its centre under the wire ; and the bowl of a wine glafs, filled 

 with two ounces of ice-cold water, being then properly placed 

 in the mixture, the thermometer wiiich ftood at 32°, was im- 

 mediately let down into the water, where it remained ftation- 

 ary for the fpace of {even minutes. A wire, cooled to the 

 freezing point was now introduced into the glafs, and the 

 water agitated with it; upon which a thick, coating of ice 

 formed on the intide of the vefiel; but no marks of congelai 

 tion were obfervable on the wire or thermometer. 



EjcJ). 2. The fame apparatus being ufed, with a mixture, Exp. 3. 



having the low temperature of 6^, the glafs was filled with ^^'^^'' ^"^ SS* 

 ,, _ . ' /• „ r> - » was cooled by 



water of 58**, m which the thermometer fell to 32° in Tfanintenfe 



minutes, by a flop watch; at which point it remained ftation- freezing mix- 



/• ■ 1 r^, 1 /- , I r t tuie. It was 



ajy five minutes longer. The glafs was then taken out of the brought to fta- 



mixture, and the water being agitated, lined the upper part tionary 32' and 



of it for about two-thirds of its depth from the brim, witii ^^-^^^111^1^' 



porous covering of ice, but the remaining part of it was free out and fhaken 



from all incruftation. '^' ^"P ^''"' 



1 will ventnre to infer from the two preceding paragraphs. Hence water 



that we have all been under a miftake in concluding that water cannot be cooled 



, 111 n 1 11 «^r.r-oi ''"d remain fluid 



may be cooled when at reft many degrees below 32" 01 l*ah- ^^ temperatures 

 renheit, without congealing ; at the fame time we are certain, below 32'', as 

 that it will preferve its fluidity, when judicioufly expofed tOp^"g^J_^ ^ "^" 

 great degrees of cold, and dilate at the fame tiipe, as Mr. The water thsr- 

 Dalton has proved. Now as the heat never falls below 32° ^°^„7;n"^i 

 in thefe experiments, the expanfion of the water in Mr. Dal- ing by fome 

 ton's thermometers, placed in a freezing mixture, cannot be<^^^"""^*' 

 afcribed to a lofs of temperature, but mutl be owing to forae 

 other caufe, probably to that which has been adigned above. 

 As for agitation, the firft experiment feems to fliew its office 

 to confift in bringing ihe water, crowded with minute icicles, 

 intocontadi with parts of the veflel much colder than itfelf, 

 wh?re it is concreted into ice. 



Exp. 3. To examine this part of the fubjed with more Exp, 3. 

 care, I formed a cup of caoutchouc, the capacity of which Repetition of 

 for caloric greatly exceeds that of glafs ; or, I belieye, that ftriitingiy in a 

 of mod other fubftances. Two ounces of water,' a little cup of caout- 

 warmer than melting fnow being poured into this cup, it was 

 placed in a mixture of the temperature of 15°^ where it re- 

 mained eight minutes without giving the leaft indication of a 

 tendency to freeze. The cup was now removed from the 

 P 2 mixture, 



