324 Relation between the Specific Gravities of [Now.. 
4, Phosphorus.—\ have made many experiments in order to ascer- 
tain the weight of an atom of this substance; but, after all, have 
not been able to satisfy myself, and want of leisure will pot permit 
-me to pursue the subject further at present. The results 1 have 
obtained approached nearly to those given by Dr. Wollaston, which 
I am therefore satisfied are correct, or nearly so, and which fix 
phosphorus at about 17°5, and phosphoric acid at 37°5, * and these 
numbers at present I adopt. 
5. Calcium.—Dr. Marcet found carbonate of lime composed of 
43°9 carbonic acid and 56°1 lime. t Hence as 43°9: 56°] :: 27°5. 
> 35°1, or 35 very nearly; and 35 — 10 = 25, for the atom of 
calcium. ‘The sp. gr. of a volume of its gas will therefore be 
1°3888, or exactly 20 times that of hydrogen. 
6. Sodium.—100 grains of dilute muriatic acid dissolved 18°6 grs. 
of carbonate of lime, and the same quantity of the same dilute acid 
dissolved only 8-2 grs. of carbonate of lime, after there bad been 
previously added 30 grs. of a very pure crystallized subcarbonate of 
soda. Hence 30 grs. of crystallized subcarbonate of soda are equi- 
valent to 10°4 grs. of carbonate of lime, and as 10:4 : 30 :: 62°5 : 
180. Now 100 grs. of crystallized subcarbonate of soda were found 
by application of heat to lose 62°5 of water. Hence 180 grs. of the 
same salt contain 112°5 water, equal to 10 atoms, and 67°5 dry. 
subcarbonate of soda, and 67°5 — 27'5 = 40 for the atom of soda, 
and 40 — 10 = 30 for the atom of sodium. Hence a volume of it 
in a gaseous state will weigh 1°6666, or exactly 24 times that of 
hydrogen. 
7. tron.—100 grs. of dilute muriatic acid dissolved as before 18-6: 
rs. of carbovate of lime, aud the same quantity of the same acid 
dissolved 10°45 of iron. Hence as 18°6: 10°45 :: 62°5: 35°1, on 
for the sake of analogy, 35, the weight of an atom of iron. The 
sp. gr. of a volume of this metal ina gaseous state will be 1°9444, or 
exactly 28 times that of hydrogen. 
8. Zinc.—100 grs. of the same dilute acid dissolved, as before, 186: 
of carbonate of lime and 11°85 of zinc. Hence as 18°6 : 11°85 :: 
62°5 : 39°82, the weight of the atom of zinc, considered from: 
analogy to be 40. Hence the sp. gr. of a volume of it in a gaseous 
state will be 2°222, or exactly 32 times that of hydrogen. | 
9. Potasstum.—100 grs. of the same dilute acid dissolved, as before, 
18°6 carbonate of lime; but after the addition of 20 grs. of super- 
carbonate of potash, only 8*7 carbonate of lime. Hence 20 grs. of 
super-carbonate of potash are equivalent to 9°9 carbonate of lime ; 
and as 9°9 : 20 :: 62°5 : 126-26, the weight of the atom of super- 
carbonate of potash. Now 126°26 — 55 + 11:25 = 60, the 
* Some of my experiments approached nearer to 20 phosphorus and 40 phos- 
phoric acid, . 
+ I guote on the authority of Dr. Thomson, Annals of Philoscphy. vol. iit. 
p. 376. Dr. Wollaston makes it somewhat different, or that carbonate of Jime 
wensists of 43°7 acid and 56°3 lime. Phil. Trans. vol. civ, p. 8. : 
