ak 
396 G. J. Brush on Boltonite, 
Si Fe Ca Mg 6 
jNo.1., 18:32 3:80 29°00 21°17 271 
The carbonic acid (82°71 per cent) was determined by the loss. 
In the second analysis, made upon the same mixture, the min- 
eral was treated with dilute hydrochloric acid, and the bases in 
the acid solution were determined and calculated as carbonates. 
The insoluble portion was decomposed by fusion with carbonate 
of soda. The magnesia in both the soluble and insoluble por- 
tions were determined by the loss. Analysis No. 2 gave— 
FeO 3°37 : 
CaC* 50°93 ¢ 72°70 soluble in HCL 
Mg6 1840 
Si 12:85 
a a 27-80 insoluble in HCL 
Mg 1177 
Assuming the carbonic acid (which was determined by the 
loss) in No. 1 to be combined with the bases in the same man 
ner as found in No.2, Kenngott shows that No. 1 contained 
28°64 per cent insoluble in acid. The percentages of. the sub- 
stances in the insoluble portions in both analyses would then be: 
Si Mg Fe Ca 
L (a 46°50 43°89 6:08 3°58 
2. (a 47-07 43°11 6-38 8-44 
Kenngott calls attention to the close correspondence between 
the analyses and insists that the method employed by vy. Hauer 
t is however worthy of remark, that the carbonic acid in 
both of y. Hauer’s analyses was determined by the loss, that the 
magnesia in both soluble and insoluble portions in No. 2 was 
also determined by the loss, and that the errors have wi 
increased more than threefold by the manner in which the 
* In the analysis the MgO is stated to be 60-93 and CaC 18°40, but the 
that follow show that this inversion is a typographical error. the original 
t To avoid misrepresentation on this important point I quote ag aus det 
article, p. 27 of the 12th No. of Kenngott’s Mineralogische Notizen< der Einfluss 
ony ied hervorgeht, dass das Grundgestein kein reiner Calcit 1s auch wurde eine 
der Luft auf das Grundgestein zei Eisenoxydul enthalt, s° wobei das 
Zweite Probe desselben Gemenges mit sehr verdiinnter dure digerirt, 
Silicat, der Boltonit, gewiss nicht angegriffen werden konnte.” 
