48 Mr Connexu’s Description and Analysis of 
ignited in a tube with potassium ; and after the excess of potas- 
sium had been removed by mercury, no trace of the smell of phos- 
phuretted hydrogen could be observed on blowing into the tube. 
When the mineral in fine powder was treated with muriatic 
acid, it gelatinized immediately, with considerable increase of 
temperature. Even when in coarse powder, there was speedy 
gelatinization of the finer particles, and the larger were gradually 
acted on. 'The external weathered coating of the mineral effer- 
vesced slightly with acid, owing to partial decomposition and ab- 
sorption of carbonic acid from the air; but the fresh mineral did 
not show the least trace of effervescence. 
In a preliminary examination of a portion of the mineral 
which was decomposed by muriatic acid, the only constituents 
found were silica, lime, a little potash, and traces of one or more 
metallic oxides. Magnesia was sought for, but none found. The 
presence of water, and absence of fluoric and phosphoric acids, 
have already appeared. 
The steps of the analysis were as follows :— 
a, 20.66 grains of the mineral, in small fragments, lost by 
ignition 3.04 grains, equivalent to 14.714 per cent. of water. 
The ignited mineral became opaque, and whiter. 
b, 24.68 grains were reduced to coarse powder in the steel 
mortar, and were treated with muriatic acid. Immediate gelati- 
nization of a part took place, with rise of temperature, and the 
mineral and acid were left in contact with one another in a 
close vessel till complete decomposition appeared to have taken 
place. From accidental circumstances, the substances were left 
in contact in the present instance for several months. It was 
thought better not to reduce the mineral to fine powder at first 
in the usual manner in a siliceous mortar, as, from the great 
tenacity and considerable hardness of the mineral, a good deal of 
silica would probably have been abraded from the mortar. 
c, Water was now added to the mass, and heat applied. Si- 
lica was separated by filtration, and, after edulcoration and igni- 
