366
Molesworth’s pocket-book
Electric Lighting.
Each separate light requires about 1 horse-power.
A “ Jabloclikoff candle
A “ Carcel burner ”
A gas burner
6 cubic feet per hour = M
Plain glass absorbs 10 per cent, of the light.
Ground „ 30 „ „
Opal 60 „
= 80 * Carcel burners
— 9} candles.
= 10
= 14 „
In lighting buildings, deep shadows are avoided to a certain
extent by keeping the light raised high above the ground, and
jltewa. inS the wails and roof or ceiling of the building
and by naving one lamp in opposition to another. Reflectors
are undesirable.
The Palais de I’Industrie, 2; acres in extent, is lighted (so
newsPaper can be easily read in any part of ths
building) by 2 clusters of 6 lamps each. The clusters are
distant horn the end of the building about | the length of the
building. '1 he lamps are worked by 12 small “Gramme"
machines, driven by 2 engines of.25 horse-power.
For lighting workshops, M. Gramme proposes a machine
with two magnets and one central ring, w hich, with 900 revo-
lutions per minute, produces a light equal to U4Ü Carcel
burners.
At Mulhouse a workshop 18? ft. long, 92 ft. wide, is illn-
muiated by lights 17 feet above the ground, 69 feet apart
long it udmal] y and 46 feet transversely.
I he smallest practicable machine is from 2 to 3 horse-
power, representing an illuminating power of about 1000
candles.
The speed of a Gramme machine varies from 500 to 1000
revolutions per minute.
Ihei “ Jablochkoff candle ” consists of two carbons about
4 to 6 millimetres thick, separated by a strip of kaolin
(china clay) about 3 millimetres thick. The kaolin when
lifted diminishes the resistance of the circuit sufficiently to
allow the electric light to be farmed between the carbons, and
nJiJTi “I’®rira<:nts at *he Lourro the Jablochkoff candle equalled
only about 40 Carcel burners.