1885.] 
and the A B C Process Vindicated. 477 
In * he f cond series > from 8-30 a.m. March 2nd to 8.30 
a.m. Mareh 3rd, the flow was still large, but the strength 
0 the sewage was much greater, being on the average 
59'9 7 g rs. per gallon. & 
vr sei * es ’ from 8.30 a.m. March 16th to 8.30 a.m. 
arch 17th, was taken in very dry weather, the sewage 
eing abnoimally rank. The suspended matter was 243*6 grs. 
per gallon. b 
In all these cases the aCtion of the process was found 
successful. Prof. Dewar and Dr. Tidy express their opinion 
that beyond all doubt “ the ABC process is capable of pro- 
ucmg a unifoim effluent, notwithstanding the very varied 
n a \ U r >? a Il d concentration of the raw material to be dealt 
W1 ^‘ d ^ e Y And that, irrespective of the original sewage, 
an effluent can easily be obtained practically clear, — that is, 
‘ containing less than one grain of suspended matter per gallon 
though the rawsewage contained a mean amount of 104*4 grs. 
pei gallon. Further, “ I he precipitation appears to be 
moie complete as the quantity of suspended matter in the 
raw sewage increases. 
But it may be said, What of the dissolved organic im- 
purities, always recognised as the most important ? Here' 
we find it stated that in the three series of experiments the 
pei centages of dissolved organic matter removed were 
respectively 74-80, 83*30, and 86*30 ! This, we submit, is a 
very different conclusion from the rash statement of the 
Rivers Pollution Commissioners that “ the process removes 
a very small proportion of the soluble polluting matter from 
sewage.” 
Nor is this all. Messrs. Dewar and Tidy find, on careful 
examination, that at least two-thirds of the organic matter 
iemaining in the effluent is diffusible, and therefore cannot 
be “ of an albuminous or complicated colloidal nature.” 
Hence it is less liable to putrefactive changes. It is, in the 
opinion of Prof. Dewar and Dr. Tidy, “ mainly composed 
of the salts of fatty acids and such like bodies.” 
Here, then, we have the first two of the Commissioners’ 
conclusions very fully exposed and disposed of. If, by 
“ allowing raw sewage to settle in subsidence-tanks,” they 
can obtain in a few hours an effluent very nearly as good, 
the sooner they prove it the better for their own credit. 
The third “ conclusion ” of Prof. Frankland and his 
colleagues was that “ the manure obtained by this process 
has a very low market-value, and cannot repay the cost of 
manufacture.” 
Prof. Dewar and Dr. Tidy find, on the contrary, that the 
