18 
BULLETIN NO. 32. 
tube of the same size as the Penfield tube. . After drying in the oven the 
plug is removed from the open tube and may be readily inserted .into the 
Penfield tube by means of tweezers. A plug above the mineral powder in 
the bottom of the tube is also an advantage, preventing any carrying over 
of solid particles with the water, and may be sealed off with the mineral 
powder. The capped tube containing the water is weighed against another 
tube as nearly as possible similar in size and weight, which has been heated 
at one end in the same way as the tube containing the water. Gradual 
ignition in a crucible with lime as a retainer gave 42*13 per cent, but on 
further and more intense ignition a loss of B 2 O s was observed. The failure 
of the lime to retain all the B 2 0 3 was probably due to the mineral not being 
in a sufficiently finely divided condition to secure the necessary intimate 
contact with the lime, fine grinding being inadvisable, and perhaps partly 
also to too rapid heating. Ignition with fused litharge also gave high results, 
probably for the same reasons. 
Figure 10 shows the loss on heating of a different sample from No. 1 
in a different oven. In this case the regulator was set for a maximum 
temperature of 110 degrees C. throughout the whole period, but the temper- 
ature on one occasion was observed to rise to 115 degrees for a short time. 
The slightly different behaviour of the two samples may be accounted for 
by differences in the gypsum content, in the initial temperatures, and in 
the air circulation of the two ovens. 
Lime was determined after volatilization of B 2 0 3 as methyl borate by 
precipitation as oxalate in dilute acetic acid solution and weighing as oxide. 
It might be mentioned that C. P. Absolute Methyl Alcohol from a prom- 
inent maker was found to contain lime and tarry substances and had to 
be redistilled before using. Boron trioxide was determined by the Gooch 
method of distillation as methyl borate and fixation in lime. Silicon, 
aluminium, iron, magnesium, fluorine, carbon dioxide, and phosphorus 
pentoxide were sought with negative results. The results of the analysis 
are tabulated below: 
Analysis 
Ratios 
Gypsum 
Ipyoite 
Theoretical 
% 
% 
CaO 
. .. 20-42 
0-3642 
0*0069 
0 -3573 or 2*000 
20*18 
B 2 O 3 
. .. 37-44 
0-5364 
0-5364 3*002 
37*68 
S0 3 
. .. 0-55 
0-0069 
0-0069 
* 
H 2 O-IIO 0 .... 
... 32*46 
1-8013 
0-.0138 
1-7875 10*032 
32*42 
H s O + liO°.... 
9*46 
0-5249 
0-5249 2*938 
9-72 
100-33 
t 
100*00 
The international atomic weights for 1920 have been used in all calcu- 
lations. The total water calculated as belonging to gypsum has been 
subtracted from the total water below 110 degrees, since gypsum loses all 
its water below 100 degrees on prolonged heating (Gmelin-Kraut II 2,235). 
The analysis agrees well with Schaffer's analysis of the original inyoite, 
except as regards the water below 110 degrees, this probably being due to a 
difference in the length of time of heating. The formula indicated by the 
above analysis is 2Ca0.3B 2 0 3 .13H 2 0 or 2CaO.3B 2 O 3 -3H 2 O+10H 2 O. 
The specific gravity of the mineral determined by the pycnometer 
method was 1 * 885 at 24 • 5 degrees C. This is slightly higher than Schaffer’s 
figure 1*875, which might be expected owing to the presence of gypsum 
(sp. gr. 2*32). 
