370 A.A. Julien on Minerals of the Key of Sombrero. 
probably from the well-known decomposition of the salt, by hot 
water, into bone-phosphate and super-phosphate (CaO, 2HO, 
PO,) of lime. : 
Two determinations were made of the amount of water in j 
the air-dried material, the assay being successively heated in each 
case in an air-bath, at various temperatures from 100° to 245° C., 
and then ignited at a red-heat. The results were as follows: 
Temperature L Il. Mean. 
z of expulsion. 
Hygroscopic moisture, 5 1388 1:071| 12°29 
Water, - - - |126°-240°C,|19-698 19°929 
- Water and org. matter,| ignition. | 6-111 6155 : 
Combined water, 25-809 26-084) 25047 
Total, ~ 27197 971551 27176 
A tendency is thus exhibited to the expulsion of the four 
equivalents of water of crystallization (in the formula below) | 
between 126°-240°C., the basic equivalent being retained until ; 
the temperature becomes much higher, or reaches ignition. The 
following is an analysis made with one gram of material: ; 
Oxygen Ratios. ‘ 
Moisture - - ~ pe tag 1-229 pinned lig ‘ 
Water and organic matter, - 25947 23°06 2752 5 
Silica, - - . . - - trace ‘ 
Sulphuric acid, - - - - eS % 
Phosphoric acid, - - - - $39°947 22°39 245 5 ee 
Magnesia, . - - - - trace, 2 
OM os oe ee BETIS 14-15. "4 4 
te Alumina and sesquioxyd of iron, - = "829 
Fluorine, - = - “ trace, 
100°346 
These figures correspond to the following composition: = 
Moisture, - - . é . é e : 1-229 a 
ROM Ae a 346 ac 
Sulphate of lime (CaO, SO,+-2HO,) es Eee 
Alumina and Sesquioxyd of iron, - - - 329 
Silica, phosphate of magnesia, and fluorid of calcium, traces. 
co Impurities, 3579 
ee <=, S180 
We 8 5050 
FO, ee ees an ee 
We eS 20-200 
Brushite, 96°823 
100-402 
De The method, employed in this and all but one of the subse- 
_ quent analyses, was as follows, the precipitates and 
filtrates 
