416 Composition and Practical Value of Native Guano. 
the process whicli for some time past Las been carried out at 
Leamington, and quite recently at Hastings, by the Native Guano 
Company. 
This Company has adopted Sillar's Patent ABC process in 
the treatment of town sewage, and professes to extract from it 
a valuable dry artificial manure, and at the same time to render 
sewage bright and clear as water, and to remove the impurities 
from it so efficiently that the clarified sewage, after treatment 
by the ABC process, may be discharged into a river or water- 
course without causing any nuisance in the immediate neighbour- 
hood or locality through which the effluent and purified sewage 
flows. Messrs. W. C. and R. G. Sillar and W. G. Wagner, in 
the specification of their patent, describe the ABC process as 
folloM's : — 
" We add to the sewage to be purified a mixture consisting of 
the following ingredients — alum, blood, clay, magnesia or one 
of its compounds, by preference the carbonate or the sulphate, 
manganate of potash, or other compound of manganese, burnt 
clay, otherwise known as ballast, chloride of sodium, animal 
charcoal, vegetable charcoal, and magnesian limestone. Of these 
substances the manganese compounds, the burnt clay, chloride of 
sodium, and magnesian limestone may be omitted, and it is not 
essential that both animal and vegetable charcoal should be used. 
If any of the ingredients named should from any cause be 
present in sufficient quantity in the sewage, it may, of course, be 
omitted from the mixture. The proportions in which the in- 
gredients are to be used vary according to the nature of the 
sewage to be purified, as, for instance, if a large proportion of 
urine is present, we increase the proportion of clay ; if the 
sewage is much diluted, we slightly increase the proportion of 
alum and blood ; if it contains a large proportion of street refuse 
we decrease the proportion of clay. 
" For ordinary sewage the following preparations have answered 
well : — 
Alum 
Blood 
Clay 
Magnesia 
Manganate of potash 
Burnt clay 
Chloride of sodium 
Animal charcoal 
Vegetable charcoal 
Magncsian limestone 
"These substances are mixed together and added to the sewage 
to be purified, until a further addition produces no further pre- 
cipitate. The quantity requiied will be about 4 pounds of the 
GOO 
1 
1-900 
5 
10 
25 
10 
15 
20 
■> 
parts. 
