TRANSACTIONS OF SECTION G. 899 
The author sums up the experience with these cranes by stating that in his 
opinion electricity applied to this purpose has proved itself to be remarkably 
efficient, even in the somewhat trying atmosphere of a foundry. 
Various practical points are then discussed relating to efliciency, cost, and 
general convenience. 
A comparison is made of the relative merits of the single motor system as used 
in the foundry, and the three-motor arrangement as in the turnery. 
Several methods of reducing the comparatively high speed of the motor to the 
slow speed of the gearing shafts, as required in cranes and similar machines, are 
described and commented upon. 
The paper concludes with a brief comparison of the merits of hydraulic and 
electric transmission as applied to cranes, pointing out that the adaptability of one 
or the other must depend entirely on the circumstances of the case, but at the 
same time showing that for travelling cranes the difficulty of conveying the pres- 
sure-water to the crane practically precludes its adoption, while in this respect 
electricity stands foremost, especially where there is a long travel. 
5. Hauperiments on the Hysteresis of Iron in evolving Magnetic Fields. 
By Professor J. A. Fuemine, F.A.S., R. Beatie, and R. C. CLinKer. 
6. Street Lighting by Electric Incandescent Lamps. 
By Witi1amM GEorGeE Watker, I Jnst.I£., A.M Inst.C.£. 
Great difference exists between the quality of the illumination required for 
the various streets of a large town. Arc lamps are undoubtedly the right thing 
for busy streets, but would prove an extravagant illumination for ordinary bye- 
streets or roads of country towns. 
It may roughly be taken that the quality of the illumination necessary is of 
two kinds—firstly, where a flood of light is necessary on account of the nature of 
the traffic; secondly, where the light is necessary for the demarcation of the 
roads, At present very little street lighting by glow lamps has been carried out 
in this country. It has, however, been tried with success on a fairly large scale 
in America and on the Continent. There are many objections to taking the 
current off the ordinary low pressure mains that serve for house lighting. Esti- 
mates show that the parallel system is generally impracticable on account of the 
great cost of the copper mains required for the proper distribution of small incan- 
descent lamps in streets. 
The parallel system becomes practical in congested districts, and where natural 
water power can be obtained. It has been felt that a way out of the adoption of 
a ‘series system’ of distribution. The main difficulty against this system is that 
the failure of a lamp filament is liable to put out all the lamps on the circuit. 
In the town of Temesvar in Hungary, nearly ten years ago, 750 16-candle-power 
lamps on the multiple series system were installed, with satisfactory results, the 
wires being overhead, 
The series system has been installed in the parishes of Kingswood and 
Keynsham, near Bristol, with considerable success during the four and a half years 
which it has been at work. 
At Kingswood, about seven miles of roads are lighted by circuits of 2, 24 and 
3 miles respectively from the central station. The lamps are spaced at 60 yards 
apart, and are elevated at from 14 to 16 feet from the level of the road on 
wooden poles, which also carry the overhead wires. 
There are 150 street lamps of candle power varying from 100 to 25, The 
indicated horse-power of the engine at full load is 32. 
The revenue from street lighting at 24d. per unit is 650/. per annum, leaving a 
clear profit of 100/., after allowing for depreciation and all expenses. Lighting 
hours, 4,250 per annum. Total cost of plant, about 3,5007. ‘The chief feature 
of this installation is the automatic cut out, so that the failure of one lamp 
