1876.] Infusorial Earth and its Uses. 347 
State Chemist of Delaware, has kindly furnished the writer 
the following record of an analysis of the “ silicated super- 
phosphate,” viz. : — 
Soluble Phosphoric Acid . . 5*855 percent 
Precipitated Phosphoric Acid . 3*327 ,, 
Insoluble Phosphoric Acid . trace 
Silica ......... 20*568 ,, 
Sulphate of Potassa .... 6*173 
According to the Messrs. Popplein’s published formula, 
the net ton of their “ silicated superphosphate ” contains— 
Infusorial Earth ....... 800 lbs. 
Dissolved Bone ....... 800 ,, 
Potash Salts ........ 400 „ 
As an absorbent and carrier of liquids of various kinds, 
and especially as a carrier of nitro-glycerine, the infusorial 
earth has been found to be most excellently adapted. It 
takes up from three to five times its weight of water, oil, nitro- 
glycerine, &c. It would doubtless prove equally valuable as 
a carrier of carbolic acid and other disinfectants, as a disin- 
fecting powder, and has possibly already found application 
for this purpose. 
In order to bring nitro-glycerine within the range of arti- 
cles of transport, Nobel, who first demonstrated its value 
in the arts, devised the production of the powder now so 
extensively employed under the name of dynamite, in which 
the explosive oil is simply carried by the inert, pulverulent 
siliceous earth. The process of the preparation of dynamite 
may be described as follows 
The infusorial earth must first be freed from water, 
organic substances, and mechanical impurities (sand, &c.) 
The first two are removed by calcining at a red heat in an 
oven with several shelves, one above the other, on which 
the earth is placed and slowly pushed from the upper to the 
lower. The organic matter, which is considered dangerous 
to the stability of the dynamite, is thus burned out. It is 
then pressed with hard rollers and sifted, which separates it 
from the larger particles and grit. It is now ready for use. 
Fifty pounds of infusorial earth are put into fiat wooden 
tanks and covered with 150 pounds of nitro-glycerine, when 
the workmen mix them with the naked hand. Gloves of 
india-rubber were at first provided, but the workmen pre- 
ferred to knead the mixture with the free hands. In half 
an hour the incorporation of the oil with the earth is com- 
plete, and the dynamite is ready for filling in the cartridge 
