though the paper be rough and soft. The method is applicable to steam
gauges, water indicators, clocks, barometers, etc., in fact, to any
measuring instrument where a moving hand can be employed.

* * * * *




A NEW MONSTER REVOLVING BLACK ASH FURNACE AND THE WORK DONE WITH IT.

By WATSON SMITH, Lecturer in Chemical Technology in the Victoria
University, etc.


The Widnes Alkali Company, limited, to which I am indebted for
permission to describe this latest addition to a family of revolving
black ash furnaces, of late not only increasing in number, but also
individual size, has kindly allowed my friend, Mr. H. Baker, to
photograph the great revolver in question, and I have pleasure now in
throwing on the screen a picture of it, and also one of a revolver of
ordinary size, so as to render a comparison possible. The revolver of
ordinary size measures at most 18½ ft. long, with a diameter of 12½
ft. The boiling down pans connected with such a furnace measure 60 ft.
in length. Each charge contains four tons of salt cake, and some of
these revolvers get through 18 tons of salt cake per day and consume
13 cwt. of coal per ton of cake decomposed.

With regard to the larger revolver, it may be just said that the
Widnes Alkali Company has not at once sprung to the adoption of a