Intelligence and Miscellaneous Articles. 



619 



Let P be a weight of powder, silica or animal charcoal, not dry 

 but taken in its natural condition. Pouring this powder into the 

 calorimeter, Q, calories are developed. Then let us dry an equal 

 weight of powder taken from the same source ; there will be found 

 a diminution of weight p, due to the water expelled. If we 

 multiply the weight p by the heat of fusion of ice, we shall obtain 

 a number of calories Q', which, added to the number Q, make a 

 sum equal to the number of calories that would be obtained by 

 pouring into the calorimeter a weight P of powder completely, or 

 almost, dry. 



A few experimental data, referred to 1 gram of silica and to 

 1 gram of animal charcoal, are given below : — 



Calories 



developed. 1'rom 



1 gr. of Powder 



not dried. 



Weight of the 



Water expelled 



from 1 gr. of 



Powder. 



Value of 

 80 xp. 



Value of 

 Q+Q'. 



ffi-52 



01383 



11-06 



17-58 



Silica...*; 6-33 



01414 



11-31 



17-64 



1^6-38 



0- 1487 



11-90 



18-28 



Animal 1 r 1P 

 Charcoal j ' 10 



0-1630 



13-04 



18-20 



The figures of the fourth column coincide, with great approxi- 

 mation, with those found directly with dry powders, as results 

 from the following data recorded in my new memoir : — 



Calories developed 



from 1 gr. of 

 well-dried Silica. 



Calories developed 

 from 1 gr. of 

 well-dried 

 Animal Charcoal. 



1766 

 17-82 

 1840 



18-17 



18-45 



18-82 



These experiments are a contribution to the new theory of solid 

 solutions. 



Venice, July 1900. 



