ed with smokeless powder is very sharp, and is as loud as
when black powder is used, yet the volume of sound is much less, so that
the report cannot be heard at so great a distance.

The report of a gun using smokeless powder is a sound of much higher
pitch than when black powder is used, and consequently cannot be heard
at so great a distance as the lower notes given by black powder.

As smokeless powder exerts a much greater pressure than common black
powder when burned in a gun, one would naturally think that the recoil
of the barrel would be greater, owing to the greater pressure exerted by
the smokeless powder on the base of the cartridge case and the breech
mechanism. However, such is not the fact; for the barrel actually
recoils very much less when smokeless powder is used. This is due to the
suddenness with which the pressure is exerted by smokeless powder, it
acting more like a very sharp blow on the metal, whereby more of the
energy is converted into heat instead of being spent in overcoming the
inertia of the barrel to give recoil. Similarly when smokeless powder is
fired in a gun, the displacement of the air is so sudden that the sound
waves do not possess the same amplitude of recoil or vibration as is
given by black powder.

* * * * *

THE CONSTRUCTION AND MAINTENANCE OF UNDERGROUND CIRCUITS.

BY S.B. FOWLER.

The numerous disastrous storms of the last winter have brought out very
vividly the advantages of having all wires placed underground, and many
inquiries have been addressed to the companies operating underground
circuits as to their success. It is not probable that all of the answers
to these inquiries have been of the most favorable character. To many
central station managers an underground system means frequent
break-downs and interruptions of service, with, perhaps, slow and
expensive repairs, which bring in their turn numerous complaints, loss
of customers, and reduced profits. In many installations burn-outs both
underground and in the station are frequent, with the natural result
that the operating of circuits underground is not there considered an
unqualified success. The writer has in mind two very different
experiences with underground cables. Several miles of cable were bought
by a certain company, carefully laid, and up to to-day not a single
burn-out or interruption of service can be attributed to failure of
cables; at about the same time anot