of electrolysis and the formation of a hydrated oxide of iron. It is not
possible, perhaps, to define the exact action, but as the formation of
an iron oxide is part of it, it seemed desirable to ascertain whether
the simple addition of a salt of iron with lime sufficient to neutralize
the acid of the salt would produce results similar to those attained by
Webster's process.

"In order to make these experiments, samples of fresh raw sewage were
taken at Crossness at intervals of one hour during the day. As much as
10 grains of different salts of iron were added per gallon, plus 15.7
grains of lime in some cases and 125 grains of lime in another, and the
treated sewage was allowed to settle twenty-four hours; the results
obtained were not nearly as good as the electrical method."

During the present year a very searching investigation of the merits of
various processes of sewage treatment has been made by the corporation
of Salford; among others of my electrical process. As the matter is at
present under discussion by the council, I am not in a position to give
extracts from the reports of the engineers and chemists under whose
supervision and control the work was done, but I may go so far as to say
that the results of my system of electrical treatment have proved its
efficiency and applicability to sewages of even such a foul nature as
that of Salford and Pendleton. The system was controlled continuously
for the corporation by Mr. A. Jacob, B.A., C.E., the borough engineer;
Mr. J. Carter Bell, F.I.C., etc., county analyst; Messrs John Newton &
Sons, engineers, Manchester; Mr. Giles, of Messrs. Mather & Pratt,
electrical engineers, Manchester; Dr. Charles A. Burghardt, lecturer in
mineralogy at Owens College.

I would also refer you to a paper recently read before the Manchester