178 EF. W. Clarke on the Atomic Volume of Compounds. 
atomic volumes of their corresponding compounds will also be 
equal. Of the truth - this I will cite a few examples, and 
tempt to illustrate the principle, and afterwards bring the excep- 
tions under another rule. 
Barium and strontium. Sr Ch, sp. gr. 2°8033, Karsten. Ba Ch, 
3°704, Karsten. At. vols., 565 and 56:2 
Sri, 4-415, Bédeker. Bal, +917, Filhol. At. vols., 77:3 and 
795, Sr H.O,, 8aq., 1:396 Filhol, Ba H?O,, 8 aq., 1°656, 
Filhol. At. vols, each 190-2. 
The sulphates and nitrates, bromids, carbonates, and simple 
hydrates, are either doubtful or exceptions. In all these 
cases the compounds of, Ba have the highest values. 
fron group. Here ae are ~ abundant that I will only 
mention a few. MnO sp. gr., 5°38, P. & J.* NiO 5597, P. 
& J. CoO 5597—5- 750, P. & J. “to 10°15, Ebelmen. CuO 
ah vara At. vols, respectively, 13 ‘0, 18-4, 138°0— 
3° 4,1 
305 4-950, PO & 2. pit ahh oe 6185, P. & J. “Ni Os 
4814 Pe Co,0, 4°814, P. & J. At. vols., 30°7, 3171 
— 34-2, 84°4, 34-4. Mispickel 'FeS,, FeAs, 6°0—6-4 Gers- 
dorffite, N iS, NiAs, 56—6°9. Cobaltite, CoS,, CoAss, 
60-63. At vols., 50-°9—54°3, 48°1—59-2, 52°6—55°3 
FeS 5-035, P. & J.: NiS 5 650, Rammelsberg ; 4601 Kenn- 
gott. CoS 5-45. At. vols., 175, 161-19 7, 16°7. Exceptions, 
MnS and CuS, having sp. grs. 3 ‘95, Dana’s Min., and 4°163, 
Karsten ; and at. vols., 21°8 and 22-9. It is worth noting 
that these two sulphids stand at the ends of the series; 
po and US, being (if they exist), wholly unstudied in this 
irection 
One more striking exception may be found by ga sh 
"eS,, MnS,, and CoS,, whose atomic volumes are very 
similar. 
Platinum group. 2KCl, PtCl,; and 2KC), IrCl, Sp. grs 
Bédeker, 3586 and 3546. At. vols., 136-2 and 1379. 
PdP, and PtP, have unequal values. 
Molybdenum and tungsten. It has bah proved by other author- 
ities that MoO, and WO, have equal atomic volumes. 
Cadmium group. CdO 69502, Karsten. HgO 11:344, P. & J. 
At. vols., 18-4 and 19°0. MgO has an a value 
which will be studied in another connec 
Phosphorus and arsenic. CusP 659, Hvoslef. CuAsT -62, Genth. 
At. vols., 33°6 and 34°9 
P.O; 2°387, Brisson. AsOs 4 he Filhol; 3°7842, Karsten. 
At. vols., 595 and 54:1— 
* Playfair and Joule. This is the eh abbreviation of the sort which I shall 
have — to bodied When I give no authority for a specific gravity, it will 
be foun + Mine eralogy,” last edition. : . 
oe 
