INYOITE FROM NEW BRUNSWICK* 
17 
by Schaller 1 (26-1 per cent below 110 degrees) for the original inyoite. 
The difference may possibly be due to longer heating of the Canadian 
inyoite. After heating to constant weight at 140 degrees in the oven, the 
covered crucible was placed on a triangle inside a larger iron crucible, so 
that the platinum crucible was distant about 1 centimetre from the bottom 
and walls of the iron crucible, and the latter was heated gradually to a 
red heat. By this procedure the mineral was slowly but thoroughly sintered 
and no loss of B2O3 was detected. Constancy of weight was reached after 
seven two-hour periods of heating, the loss, 41*92 per cent, being accepted 
as the best value for the total water. Another half gram portion was heated 
in the same oven at a constant maximum temperature of 105 degrees. 
After six days the loss was 32*40 per cent and after eleven days 32*44 per 
cent, with no more loss on further heating. The long time required to drive 
Figure 10. Graph showing water loss of inyoite on heating at 110 degrees C. 
* 
off the last 1 or 2 per cent of water below 110 degrees was no doubt due to 
the presence of relatively coarse particles in the crushed material used. A 
sample of uniform grain size would be necessary for strictly accurate results. 
After the loss of 30 per cent of water the material becomes decidedly hygro- 
scopic and the rate of loss will* evidently depend to quite an extent upon the 
humidity of the air entering the oven. The sample which had lost 32*44 
per cent of water gained 11 mg. in weight on standing in a covered crucible 
for four hours in the balance case. Other methods of determining the total 
water were also used and yielded fairly concordant results. Using a Pen- 
field tube with lime as a retainer 42*01 per cent water was obtained. The 
modification of the ordinary Penfield tube method which was used might 
be noted here. When large amounts of water are determined in the Pen- 
field tube there is difficulty in holding the water with the usual plain or 
bulb forms. The writer substitutes for the bulb a plug of glass wool which 
holds the water like a sponge by capillary attraction. The plug is pre- 
pared in advance by inserting a sufficient amount of glass wool into an open 
1 U. S. Geol. Surv. Bull. 610, p. 39. 
