some of the Substances which accompany it , &c. 331 
1. 100 grains of sapphire, pulverized in the agate mortar, as 
above stated, had increased to 105. These 105 were mixed 
with 250 of calcined sub-borate of soda, and put into a platina 
crucible. They were then exposed to a violent heat for two 
hours, and afterwards allowed to cool. The mass was vitrified, 
and had the appearance of a greenish blue glass, fissured in 
many directions. 
2. This glass being strongly attached to the platina crucible, 
the whole was put into muriatic acid, and boiled for some hours. 
By these means, a total and limpid solution was obtained. 
3. The matter of the stone was next precipitated, by ammonia 
not entirely saturated with carbonic acid ; the liquor was filtered ; 
and the precipitate well washed and dried. It was then redis- 
solved in muriatic acid, and evaporated. 
4. By this evaporation a precipitate was formed, which, when 
well washed and ignited, weighed 10,25 grains, and was silica. 
5.. The liquor, together with that which had washed the pre- 
cipitate, was boiled in a silver vessel, with an excess of potash 
this redissolved all the precipitate, except one grain. 
6 , Muriate of ammonia was poured into the alkaline solution, 
(No. 5.) The potash expelled the ammonia from the muriatic 
acid, and, forming muriate of potash, could no longer retain 
the earth in solution ; a very copious precipitate, therefore, was 
formed. This precipitate had all the properties of alumina ; and, 
when well washed and ignited, weighed 92 grains. Conse- 
quently, deducting 5 from the silica, for the abrasion of the 
mortar, we shall have for result, 
Silica 
Alumina 
Iron 
Loss 
5,25 
92 
1 
L75 
100,00 
