th the first quantity, and five with the second. The distance between
Heinrichsalle and Wilhelmstrasse, where the engine performed the regular
service, is 1 kilo, and there are gradients

Of about 1 in 30 in 400 meter length.
" 1 " 45 " 250 "
" 1 " 72 " 350 "

This distance was traversed sixty-four times, the total distance,
including the journeys to the station, being 66 kilos. The engine gives
off fully 15-horse power on the steepest gradient, the total traction
weight being 81/2 to 9 tons; it is worked with an average steam pressure of
5 atmospheres, and has cylinders of 180 mm. diameter and 220 mm. stroke,
cog wheel-gear of 2 to 3, and driving wheels of 700 mm. diameter. The
quantity of water evaporated during the service time of 101/2 hours was
found to be about 1,600 kilogs., consequently about 800 kilogs. steam was
absorbed by one quantity of soda, the weight of which was ascertained at
about 1,100 kilogs. The averaging heating surface is 9.8 square meters;
the difference of temperature between soda lye and water was toward the
end only 3 deg. Cent.; 234 kilogs. pitcoal were used for boiling down the
lye for the 101/2 hours' service, which corresponds to a 6.6 fold
evaporation.

(Signed) M.F. GUTERMUTH,

Assistant for Engineering at the Technical High School.

HASELMANN,

Manager of the Aix la Chapelle-Burtscheid Tramway.

Here are some unquestionable results. For nearly a year the first railway
engine, and for six months the first tramway engine of this new
construction, have been introduced into regular public service, and been
open to public inspection as well as to the criticism of the scientific
world. They are worked with greater ease and simplicity than ordinary
locomotive engines; the economy of their working appears, allowing for
shortcomings unavoidably attached to small establishments, to be at least
equally great: they do not emit either steam or smoke, and their action
is as noiseless as that of stationary engines.

In view of these facts it might be expected that railway managers, who
are continually told that the smoke of their engines is a serious
annoyance to the public, would be eager to make themselves acquainted
with them; it might, in particular, be expected that the managers of the
underground and suburban railways of this metropolis would lose no time
in making experiments on their own lines--if only by converting some of
their old engines into those of the