296 Analysis of Wacke. 
Earthy phosphate of iron has recently been found at Hop- 
kinton, Mass. It exists there in large quantities, and is em- 
ployed as a pigment. The gentlemen on whose grounds it was 
found sent me several pounds of it. 
g = E ie F. AF 
Arr. XVI. Analysis of Wacke, by Dr. J. W. WesstTer, of 
Bost 
on. 
On E hundred parts exposed to a red heat in a platina cruci- 
ble lost 18.5, acquired an umber brown color, and a degree of 
hardness sufficient to scratch glass. 
One hundred parts reduced to fine powder were mixed with 
four times the weight of soda, and exposed to heat, gradually 
increased for three quarters of an hour; at the expiration of 
which time the whole had acquired a pasty consistence. e 
crucible was now removed from the fire, and its outer surface 
carefully wiped. Muriatic acid was poured on till all efferves- 
nce ceased. The solution obtained was evaporated to dry- 
ness, gradually assuming an orange red color. Water was 
now poured upon the mass, after which it was filtered, and the 
remaining powder carefully dried; after ignition, and whi 
warm, it weighed 28 parts. This powder was insoluble inme 
riatic acid, and of a white color. 
To the filtered solution, reduced by evaporation, carbonale 
of potash was added, the precipitate was collected on a filter, 
washed and dried: it weighed 23. parts. ’ This powder was 
redissolved in sulphuric acid, sulphate of potash added, and 
crystals of alum finally obtained; hence this powder was alu- 
mine. To the liquor from which the silex and alumine had 
thus been separated, acetic acid was added; the whole evap- 
orated to dryness; the excess of acid being removed, a small 
quantity of water was poured on, and after strong ignition, the 
precipitate weighed 4.5. 
Into a very small tubulated retort I introduced a portion 
from the same mass, whence the piece submitted to analysis 
