Chemistry. ^15 
known. “ If we join,” says he, two pieces, one of lead, and 
the other of silver, so that their two edges form the same plane, 
and if we bring them in contact with the tongue, we shall feel 
a taste approaching to that of vitriol of iron, whereas each piece 
taken separately produces no taste whatever. Is it not probable, 
that by this junction of two metals, there takes place a solution 
of one or other of them, and that the particles thus dissolved in- 
sinuate themselves into the tongue.^” We have taken this curi- 
ous passage from Aldini’s General View of the Application of 
Galvanism to Medical Purposes^ p. 95. just published. 
II. CHEMISTRY. 
10. Relation between the Specific Heat of Bodies and the 
Weight f their atoms. — In our last Number we mentioned the 
beautiful discovery of MM. Dulong and Petit, that the speci- 
fic heats of bodies are inversely as the relative weights of their 
atoms. Hence, the products of the weight of any atom by its 
corresponding capacity for heat, will be a constant quantity ; and 
it also follows, that the atoms of all simple bodies have exactly 
the same capacity for heat. The following Table shews the re- 
sults obtained by these able chemists. 
Names of Metals. 
Specific Heat, that 
of Water being 
Unity. 
Relative weights of 
the Atoms, that of 
Oxygen being 1. 
Products of the 
weight of each 
Atom by its corre- 
sponding capacity, 
4.8777. 
Bismuth, 
0.0288 
13.30 . 
0.3830 
Lead, 
0.0293 
12.95 
0.3794 
Gold, 
0.0298 
12.43 
0.3704 
Platinum, 
0.0314 
11,16 
0.3740 
Tin, 
0.0514 
7.35 
0.3779 
Silver, 
0.0557 
6.75 
0.3759 
Zinc, 
0.0927 
4.03 
0.3736 
Tellurium, 
0.0912 
4.03 
0.3675 
Copper, 
0.0949 
3.957 
0.3755 
Nickel, 
0.1035 
3.69 
0.3819 
Iron, 
0.1100 
3.392 
0.3731 
Cobalt, 
0.1498 
2.46 
0.7685 
Sulphur, 
0.1880 
2.011 
0.3780 
The mean of these results is 0.3752, so that if we call S the 
specific heat of the body, and W the relative weight of its 
atoms, we shall have S 
0.3752 
W * 
E e 2 
