ESPECIALLY ADAPTED TO THE MANUFACTURE OF SULPHATE OF AMMONIA.
INVENTOR, ALEX. ANGUS CROLL.[1].

[Footnote 1: Read at the recent meeting of the Gas Institute,
Glasgow.]

BY GEORGE ANDERSON, OF LONDON.


The paper I have to lay before you describes the last product of the
brain of one of your past presidents--Alexander Angus Croll--in
connection with our industry. It may not be so well known to some of
the younger as it is to many of the older members of the Institute
that the fertile brain of Mr. Croll has done much for the improvement
and the extension of the gas industry. I consider that he has been the
most successful pioneer both in the cheapening and the purification of
gas--two elements without which our industry would progress but slowly
if at all; and the success which has crowned his efforts, to our
advantage, has reflected itself favorably on himself, showing by his
financial success that he has also been a good man of business. All
these are conditions which enhance the value of this paper. In the
present instance, I claim no other credit than that of being the
mouthpiece of Mr. Croll, whose assistant I was for ten of the busiest
and most important years of his eventful life; and having (with my son
Bruce) taken part in the experiments, I have been asked to describe
the process to the Institute.

The manufacture of sulphate of ammonia, as hitherto conducted, has
consisted either in bringing together sulphuric acid and ammoniacal
liquor or in distilling the liquor by external heat, or by the