The under side of the reflector, which is made of enamelled iron
disposed in the form of a flat inverted cone, reflects the upward
rays from the lamp and causes the extreme ones to strike the ground
at a distance of about 50 metres from the foot of the lamp-post. The
increase of lighting effect in the streets due to those reflectors
is very marked. The upper part of the reflector serves the purpose
of a case and weather protector for the automatic lamp-switch which
is inserted from the top, and the lower end of which is fitted with
copper hooks to which the two lamps are fixed. The glow lamps are
fitted with holders of a type designed by the engineer, which provide
the lamp terminals with large and strong eyes affording considerable
contact surface and adapted for hooking on direct to 2·5 mm. copper
wire, the ends of which have merely to be bent into a suitable form for
maintaining the lamp in any required position. These lamps are of an
improved Lane Fox type, manufactured by the Electrical Company, at
their works in Vienna. Although originally intended for 16 candle-power
lamps they have so far been worked at 18 candle-power, taking 53·618
volts and about 1·183 ampères, which is equivalent to 3·522 watts per
candle-power, or about 211 candles per horse-power. The current is
maintained at 10 ampères, and the potential between independent groups
of lamps is 53·6 volts. The aggregate energy lost, in overcoming the
resistance of the main leads, switches and cut-outs, is 12·8 per cent,
of the total electrical energy generated at the central-station—a
very satisfactory result on a system of over 37 miles of streets. The
electro-motive force in the conductors is about 1,400 volts, which is
below the normal capacity of a Brush machine, thus allowing more lamps
to be operated from the four machines. The machinery is driven by a
300 horse-power horizontal compound-condensing tandem steam-engine,
running at the normal speed of 100 revolutions per minute. During the
first 1,200 hours of lighting, only three lamps out of 760 failed, and
one of these had been broken maliciously. The engineering arrangements
are due to Mr. C. F. de Kierskowski Steuart, M. Inst. C.E., the
various difficulties incidental to a novel work having been surmounted
with experienced workmen. Although the system at Temesvar has more
complicated arrangements than are now required if secondary generators
are used, it has shown that it is quite practicable to light all the
streets in a town by electricity; also it has enabled a comparison to be
made between the useful effect obtainable from arc and from glow
lamps. Each group of glow lamps was found to absorb practically the
same energy as one arc lamp of from 800 to 1,000 candle-power, and
ninety-one or ninety-two of these could have been run with the same
expenditure of power as 731 glow lamps. The eight glow lamps forming
one group are in many cases scattered in different streets, often quite
out of sight of each other. Under such circumstances, the substitution
of one light centre, however powerful, for every eight could only be
done by leaving many spots in complete darkness. To give a usefully
diffused light by means of arc lamps, their number would have to be
considerably greater than ninety-two, or, in other words, the standard
of street lighting would have to be raised, and for this the town was
not prepared to pay.
The business has now passed into the hands of the Anglo-American
Corporation of London, who are extending the installation by placing
alternating current dynamos at the station to work transformers for
the supply of houses so as to utilise the original plant for street
lighting only, as, even with the advanced knowledge of the present day,
it is doubtful whether for this purpose a more economical system could
be employed.