The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1895-02-17

chine, which difference increases as the
belt deteriorates, the loss in the electric
drive being about 20 per cent with SLOW
speed motors, but less than that where 1t
is possible to place the motor overhead
and drive from that position, using a wide
belt to the machine. Second-The exclu-
sion of countershafts and overhead bolt
ing, thereby allowing the free and unob-
structed use of overhead travelling cranes.
Third-Greatest range of speeds. In
42-inch lathe the number of speeds
with belt drive triple-geared) was
fifteen and with the electric twenty
seven, both in either direction.
Fourth-Instant change of speed from
maximum to minimum or to any
intermediate, and also instant reversal.
With the bclt-drive a change of speed re-
quires either shifting of belt or change
of the gearing, both consuming time.
Fifth-Reduction or eliminating entirely
the wear and tear on belts and their &C
companying loss in transmission. The
electric drive is practically of the same
efficiency until worn out. Sixth-No
power is consumed by the machine or any
of its accompanying parts, such as coun-
tershafts, except when actually in use
and doing work. Seventh-The machine
can be placed in any part of the shop, and
at any angle with the line shaft, thereby
utilizing to the utmost all the floor space,
and allowing the machine to be located in
the most convenient place or position for
the work which it has to do. This is also
advantageous in cases where it is more con-
venient to move the machine than the
work.
ELECTRIC DRILLS IN Nova SCoTIA.-In the
Windsor gypsum quarries, Nova Scotia,
portable electric percussion and rotary
drills have lately been introduced success
fully by Canadian firm. The percussi on
drill in general external appearance con-
forms very closely to the regular type of
steam and air drill; in fact, the tripod and
shelf are of the standard steam-drilI form.
Electrically, it is arranged in the form OF a
solid piston, reciprocating in a magnetic
field and controlled thereby. The piston
is provided with a standard airdrill rotat-
ing rifie-bar and the usual form of springs
to protect the front head of the drill from
blows. The drill has a piston diameter of
3M inches, a length of stroke from 6% to
So inches, length of feed a inches, num-
Der of blows per minute $50 to $50. The
first of these drills was installed on the Ca
madam $500" canal last winter, when the
contractors We're greatly pleased with its
performance. On these works the perform
ance was equal to that of three steam-drill,
and the facility with which the drill could
be moved, owing to the complete tiexibility
OF the connections was especially remarked.
ELECTRIC LIGHT PHoToGRAPHY.-Mr. Ad-
amson of Glasgow, Scotland, has been ex-
hibiting Photographic apparatus using
so candlepower incandescent lamps, about
forty in number, arranged in a circle inside
an umbrella-shaped reflector. The lamps
are run up to double or treble their normal
power at the moment of exposure. This,
as every electrician knows, will not only
blacken the lamps at once, but shorten
their life at the same time The arc lamp
is now so perfect, its light is so much
better than daylight for portraiture work
and the cost for maintenance and for cur
rent SO small compared with that of the
incandeScent system, that experts fail to
see the reason for the adoption of mean
descent lamps for such purpose. Perhaps
the greatest use for the arc light in photo
graphic work now occurs in American
newspaper offices where resort is made to
free illustration. The speed and neatness
with which latest sketches from the seat OF
war, crime or disaster are thus converted
into blocks and are run through the press
alongside type is considered marvellous by
foreign journalists.