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.

* * * * *




IMPROVED CHANGEABLE SPEED GEARING.


This is the invention of Lawrence Heath, of Macedon, N.Y., and relates
to that class of changeable speed gearing in which a center pinion
driven at a constant rate of speed drives directly and at different
rates of speed a series of pinions mounted in a surrounding revoluble