e by a watch key.

Besides this, the magnified reading of course magnifies any primary
error, and is largely dependent on the accuracy of the mechanism.

* * * * *

THE ALBO-CARBON LIGHT.

We need hardly remind our readers that numerous unsuccessful attempts
have been made at various times to enrich ordinary coal gas by the aid
of volatile oils. Upon the present occasion we have to place before
them particulars of a process having the same object in view, but
which is so far dissimilar in that it deals with a solid substance
instead of a liquid oil. The invention has been brought into its
present practical shape by Mr. James Livesey, C. E., of No. 9 Victoria
Chambers, Westminster, in conjunction with Mr. Kidd, with whom it
originated. The process consists in the employment of a substance
called albo-carbon, which is the solid residuum of creosote. This
material is moulded into the form of candles, which in large lamps are
placed in a metallic vessel or receiver near the gas burner. The
albo-carbon is warmed by the heat of the burning gas, the heat being
transmitted to the receiver by a metallic conductor. Upon the
albo-carbon being raised to the necessary temperature it volatilizes,
and as the coal gas passes over it to the burner its vapor becomes
mingled with the gas, and greatly raises its illuminating power. Of
course when first lighted the coal gas only is burned, but in a few
minutes the albo-carbon communicates its enriching vapor to it. The
only alteration necessary to the present gas fittings is the
vaporizing chamber, which is of simple construction, although at
present the details of the various arrangements necessary for the
different kinds of lights have not yet been fully worked out. This
invention is now being tried experimentally in the eastern section of
the Westminster Aquarium, where we recently examined it, and found it
to afford a marked improvement upon the ordinary system of gas
illumination, although a smaller number of burners is being used.
Tried alternately with ordinary coal gas, the higher illuminating
power of the albo-carbon light was very remarkable. It appears that
there are 200 burners fitted at the Aquarium with the new light, and
these successfully take the place of 500 ordinary gas burners
previously in use. The illuminating effect is stated to be doubled,
with an additional advantage as regards economy. The reduction of cost
arises from th