_Journal_ of the Society.]

By WM. WEBSTER.


The term sewage many years ago was rightly applied to the excremental
refuse of towns, but it is a most difficult matter to define the liquid
that teems into our rivers under the name of sewage to-day; in most
towns "chemical refuse" is the best name for the complex fluid running
from the sewers.

It is now more than ten years since I first commenced a series of
experiments with a view of thoroughly testing various methods of
purifying sewage and water contaminated with putrefying organic matter.
It was while investigating the action of iron salts upon organic matter
in solution and splitting up the chlorides present by means of
electrolysis, that I first became aware of the importance of
precipitating the soluble organic matter in such manner that no chemical
solution should take the place of the precipitated organic matter. If
chemical matter is substituted for the organic compounds, the cure is
worse than the disease, as the resulting solution in most cases sets up
after precipitation in the river into which it flows.

My first electrolytical experiments were conducted with non-oxidizable
plates of platinum and carbon, but the cost of the first and the
impossibility of obtaining carbon plates that would stand long-continued
action of nascent chlorine and oxygen made it desirable that some
modification should be tried. I next tried the effect of electrolytic
action when iron salts were present, but did not think of using iron
electrodes until after trying aluminum. I found that the action of