toad 
ea 
* RR ee, 
Ey = 
& determined by Prof D: 
Sented in figs, 1, 2, ba 3. niphe measured angles are as follows: 
on the Ammonia-cobalt Bases. 247 
acteristic reactions. In other cases, and especially when a little 
chlorid of cobalt was originally present, warm water dissolved 
out another sulphate, crystallizing in octahedra of an orange-red 
color, the examination of which is not yet complete. 
ye are unable to confirm Frémy’s assertion that sulphuric 
acid precipitates from oxydized ammoniacal solutions of sul phate 
of cobalt, an acid sulphate of Roseocobalt, having the formula 
5NHs.CozO02, 5S0s+dHO. 
The salt precipitated under these circumstances is merely the 
neutral sulphate, as repeated analyses have shown, and as the 
crystalline form at once proves. The formula of the neutral sul- 
is 
NHs. Co20s, 3503 +5HO, 
5 
as the following analyses show: 
08160 grs. gave 03800 grs. sulphate of cobalt = 1772 per cent cobalt. 
08272 urs. gave 03869 grs, “ es tia * + 
02760 grs. gave 0 2908 grs, sulphate of baryta == 36°11 per cent sulphurie acid. 
05731 grs. zave 08074 gre.“ S = 3638 - 
14925 ors, gave u8250 yrs, water oe 6:14..." hydrogen. 
12840 grs, ¥Yave { 109 g' c ” = 6 15 rT rr 
12108 grs, gave 2205 ©. ¢. nitrogen at 18°4 C. and 761™™-28 (at 18°-9) = 201-97 
© ¢ at U° and 760” = 21 08 per cent nitrogen. 
The formula as above stated requires 
Eqs, Calculated. Found. Mean. 
Psi greet Re HRS sd ie BMI Rae 
Cobalt, - 9g 590 17°71 1772 1779 1775 
Sulphuric acid, 3 1200 3603 3611 3638 3624 
Hydrogen, - 20 200 600 614 615 6 1+ 
Nitrogen, = - 700 2102 2095 20:08 atwl 
Oxygen, - 8 610 1994 18 86 
3330 10000 100-00 
_ The sulphate of Roseocobalt has a fine cherry-red color, The 
light reflected from a layer of the crystals when analyzed by the 
dichroseopic lens, gives a rose-red ordinary, and an orange-red 
extraordinary image. “The dichroism is very distinct. In this, 
#3 in our other observations upon dichroism, the reflected rays 
examined made an angle of about 60° with the normal, but no 
