ON LATENT HEAT. 4^' 



On the whole, therefore, it appears that we (hall not exceed Mean refult 

 the truth when we eftimate the latent heat of bifmulh at 550''. tn^^^^'atof^bifl 



I made, in hke manner, two experiments to alcertain the math, 

 latent heat of tin, and of thefe the refults were— 



Experiments oa 

 tin. 

 Latent heat 

 S07» 



This agrees remarkably well with the determination of this Latent heat of 

 point, faid to have been made by my father, in Black's ''"'^ ^^^ 

 Ledures. 



Zinc is computed, by Bergman, to melt at 700** of Fahren- 

 heit's thermometer. Taking that for granted, I made three 

 experiments on the latent heat of zinc, in a iiuuiar way with 

 that already related with bifmuth. The refults were as 

 follow : 





In thefe experiments no allowance is made for lofs by fleam, Latent heat of 

 which, however, by the dexterity acquired by pradice, I was ^^ *^ 

 enabled to render very fmall. 



Lead I found to melt at a point above 584®. Owing to the 

 Ihortnefs of the thermometric fcale, I could obferve no higher. 

 I fuppofe therefore that 594*^, as found by Dr. Irvine, cannot 

 be materially diftant from the truth. Afiuming it as true, I 

 proceeded to make feveral experiments on the latent heat of 

 lead. In doing this I was led immediately to notice, that 

 melted lead does not by any means produce fo much fteaai as 

 other metals do when poured into water, even under the mofl 

 carelefs management ; and of this the reafon will appear from 

 the followinij table : 



Vol. IX.— Septemjbkr, 18Q4. 



Exptriments 



