would be
impracticable, and probably unwise, to alter much of the existing
machinery, but, by the adoption of the best known types of electrical
plant, and air compression in our new and deep mines, the consumption
of coal per horse power would be reduced, and the extra expense, due
to natural causes, of producing minerals from greater depths would be
substantially lessened. The consumption of coal at the collieries of
Great Britain alone probably exceeded 10,000,000 tons per annum, and
the consumption per horse power was probably not less than 6 lb. of
coal, and it was not unreasonable to assume that, by the adoption of
more efficient machinery than was at present in general use, at least
one-half of the coal consumed could be saved. There was, therefore, in
the mines of Great Britain alone a wide and lucrative field for the
inventive ingenuity of mechanical engineers in economizing fuel, and
especially in the successful application of new methods for dealing
with underground haulage, in the inner workings of our collieries,
more especially in South Wales, where the number of horses still
employed was very large.

STEAM TRAMS AND ELECTRIC TRAMS.

Considerable progress had within recent years been made in the
mechanical appliances intended to replace horses on our public tram
lines. The steam engine now in use in some of our towns had its
drawbacks as as well as its good qualities, as also had the endless
rope haulage, and in the case of the latter system, anxiety must be
felt when the ropes showed signs of wear. The electrically driven
trams appeared to work well. He had not, however, seen any published
data bearing on the relative cost per mile of these several systems,
and this information, when obtained, would be of interest. At the
present time, he understood, exhaustive trials were being made with an
ammonia gas engine, which, it was anticipated, would prove both more
economical and efficient than horses for tram roads. The gas was said
to be produced from the pure ammonia, obtained by distillation from
commercial ammonia, and was given off at a pressure varying from 100
to 150 lb. per square inch. This ammonia was used in specially
constructed engines, and was then exhausted into a tank containing
water, which brought it back into its original form of commercial
ammonia, ready for redistillation, and, it was stated, with a
comparatively small loss.

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