228 HAROLD L. ALLING 
PECIFIC GRAVITIES 
MgS 04°7 H20 -Fe $0..:7 H,0 
Re, 
aa 
Fe Salt 10 20 30 40 50 60 70 80 90 F. Sait 
Msg Salt 90 80 70 60 S50 40 30 20 10 McSait 
® Hintze, K,0% 
® VanHise, Ortho. 
® VanHise,Micro. 
© Rammelsberg 
O Bayley 
@ Lacroix 
‘le 
| ae 
le 
smp_|<¢ 
a 
Sd 
es 
K- Fela 90 680 70 60 S50 40 30 20 10 K-Fold. 
Fic. 6.—The specific gravities of the hydrated sulphates of iron and magnesium 
after Regers, and the specific gravities of the potash-soda series based upon data 
supplied by Hintze. Both diagrams illustrate the fact that the densities of dimorphous 
forms are different. 
