M. Godon’s mineralogical observations. 147 
a rigorous estimation of the quantity of each alkali. From the pro- 
ere of Roe of paush rated af two-thirds of the saline mixture, 
to thebasis taken from Bergman, the quantity of alkali has 
been wets at 2,50 grains for the potash, and 0,90 for the soda; or 
0,41 parts potash, and 0,11 soda, of the original weight of the mineral 
employed. | 
In uniting the above results, we may admit that argilloid has giv- 
en, in the fifteen hundredth parts diluted by sulphuric acid, 
~ Lime ‘ : ‘ ' a 5,50 
Alumina, stained by the sands of iron and manganese, 6,75 
en ee erties Woe ee et Porter me pre ee 
Soda. esnips oy 
| Loss, consisting of water and carbonic acid, . . 2,23 
The proportion of silica existing in argillaceous schistus, petrosilex, 
&c. being ascertained, by many analyses, never less than 55, if we 
suppose, that those parts beyond 55, which had not been attacked by 
the acid, contain a quantity of the other substances proportional to 
that above mentioned, we may calculate, on an average, at about 
one hundredth, the proportion of alkali contained in the argilloid sub- 
mitted to this examination. 
This analysis, to which the situation of a traveller did not permit 
me to give a greater degree of accuracy, is sufficient to establish the 
important fact of the existence of potash and soda as elements in 
some rocks in this part of the world. 
Klaproth, in his analysis of the klingstein of pieiies a moun- 
tain in Bohemia, supposes the quantity of soda contained in this mineral 
