ELISHA MITCHELL SCIENTIFIC SOCIETY. 67 
Theory for R’A1,Si,O,, . 3H,O 
where R is +Ba, 32Ca, 2K. 
aki iiek 4 ABW 42°87 
Bihiks ligt.) 94; 54 24:27 
Eek) Ca ierts Bak O65 6°62 
CaO a el oat VOLO FEF 
BO a uta). oy SOB 6°10 
ae eee A 3-10 12°87 
100.00 100°00 
Experiments were made to determine at what temper- 
atures the water was driven off, and the results are 
given in the following table, the mineral being heated in 
each case until the weight became constant. The last 
trace of water could only be driven off by heating the 
mineral over the blast lamp. 
Loss. 
Pee ee Re Priinething. 
‘OS eR SRE A IES Aarts Pere | 1°93 } 
Whe bs Ao as 1°48 } 4°33 
200 Bhi Ole ace LAA ht 300 1 
260 LENE UP be eg ee et Oe! Eee ee fe sm peer 
alt Si EE ere a WY ea 
MSN neat ei teh. ph ta one 14) 4°9G5) 5.99 
Raper ae WAM oo vn a}. fag Sart. 
28 ta IDS Sg Ti ie tre Se FP Ze 
As 18 seen from the above, about one-third of the wa- 
ter, or one molecule, is given off between 100° and 200°, 
anether third approximately between 200° and 300°, 
while the remainder is expelled only at an intense heat. 
This would indicate that the water exists in three differ- 
ent conditions in the molecule. If only that which is 
expelled below 200° be regarded as water of crystalliza- 
tion, the composition would be H,R’ Al, S1,O0,,+ 4,0. 
That the new mineral would be closely related to the 
