The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1895-08-11

electro-motor at regular intervals, the con-
tact controlling the magnet being con-
nected with some moving part OF tno
clock. The great difficulty hitherto has
been the unreliability OF this contact, oW-
ing to the small amount of power ayallapie
for making it, but by new devices absolute
certainty OF action can now be insured.
But while it is possible for every one to
have his own automatic clock-wlnder,
a system called the 'ssynchronome, has
been introduced which still further slmpl1-
fies the regulation and operation OF time.
keeping devices. This system consists OF
one pendulum, kept in motion by means
of two wheels and an electro magnet, which
derives its energy from small dry cell.
The object OF the pendulum is to transmit
electrical impulses at regular periods along
single wire to any number OF clock
faces. whether in house, a public
building or church-tower, the hands
being "synchronized'' forward by each
of these impulse s. 1t thus becomes pos
sible with both winding aud clock works.
If desired house or building can be sup
piled with its own synchronizer, which
controls Its own circuit. In this way
every room in the house can be supplied
with the time of day to within a variation
OF one second per month. The device is
usually placed in the hall and the actuated
dlals can either be placed on the mantel
shelves of the various rooms or suspended
on the walls with flexible cord, as the. alb
sence of mechanism enables them to be
treated artistically, and suggests their
combination with drawing room art work
in wrought-iron and wood-carying. The
electric movement can be fitted into any
existing clock-ease, and striking or Ginning
may be accomplished by all or any of the
dials. The wiring Is very simple, consisting
of the connection of one dial with another
by single line. For putting forward the
hands of all the dials a push button is pro-
vided on one of them. For setting back it
is sufficient to move the hands OF this dial
only and all will be altered.
The UTILITY OF LIGHTNING Rops.-Alex-
ander Meade has collected some interest
ing statistics regarding the frequency and
severity of thunderstorms. About 260peo-
pie are killed annually by lightning in the
United States. Of these casualties usually
only one death occurs in each of January,
February, November and December. In
March, 3; April, ID; May, %; June, II;
July, So; August, 46; September, Is; and
October, II. The annual loss by fire due
to lightning strokes is estimated at two
and half million dollars. Of the annual
number of SIS buildings set on fire, accord
ing to last years weather returns, $40
WClC otSOlCo o"o Sle'hoiAOS, ~
were churches and 131 were dwell
ings. The region of greatest fire.
quency of thunderstorms in the United
States is in the southeastern portion, ex-
tending from Georgia to Mississippi,
where, on the average, forty storms occur
each year. In the northern part of the
United States the number is only twenty
and on the New England coast but ten.
To the west and southwest of the Great
Lakes thunderstorms occur most frequent
ly in May or June, and to the south and
east in July and August. The general
direction of approach in the United States
is from the west; but in Southern Florida
the storms approach from the east, thus
following the direction of the general
movement of the atmosphere. Mr. Nc
Adie recommends that lightning rods
should be either OF copper-tape weighing
six ounces to the foot, or OF iron
rod or tape weighing thirty-five ounces
to the foot The top of the rod should
consist of clusters of points, which have
been plated to prevent corroslon or rust.
The grounding of the rod should be in
damp earth or running water and inde-
pendent grounds.are preferable to water or
gas main pipes. In spite of all that has
been calculated or suggested on the point,
there is no definite area of protection de-
pending on the height of the rod. The
risk of a lightning stroke is about five
times greater in the country than in the
city. In fact, it is hardly necessary to
place rods on the ordinary block dwelling
houses of the city.