740 EEPORT 1889. 



gums used in the preparation of the varnishes employed in the manufacture of 

 antifouling compositions with the various antifouling materials employed, so that 

 the composition may be quite reliable even in cases where the paints now used 

 sometimes fail to fully answer their purpose. 



MONDAY, SEPTEMBER 16. 



The following Papers were read : — 



1. The Distribution of Electricity from Accumulators} 

 By Major-General Webber. 



2. Precautions to be adopted when the Electric Light is supplied ly means of 

 Transformers.'^ By Killingworth Hedges, M.Inst.C.E. 



In a paper entitled ' The Fire Risks of Electric Lighting,' which was read at the 

 Southport meeting of the British Association in 1883, the author urged, he believes 

 for the first time in this country, the necessity of regulations and the adoption of 

 proper safety appliances. The fire insurance companies have imiversally recog- 

 nised the importance of having the leads iu the houses thoroughly insulated and 

 protected by cut-outs, and the rules which have been published by the Institution 

 of Electrical Engineers, and by some of the leading fire insurance offices, have 

 been so far successful that no fire of any magnitude has been caused by the electric 

 light. 



In this paper the author treats of a new danger which may occur when 

 transformers are employed to convert currents of high tension into the pressure 

 suitable for the incandescent lamps. The danger of fire may be obviated by 

 thorough insulation, but should an alternating current of 1,000 volts or more 

 break through the transformer into the house circuit, a dangerous shock might be 

 taken by anyone inadvertently touching the lampliolder or some unprotected part 

 of the circuit, if any portion of his body was in connection with a wire of opposite 

 polarity, or in some instances with the earth. Such an accident might possibly 

 occm-, although the lamps would give no indication that the electro-motive force 

 was more than normal. 



The conditions which would cause such an effect are stated, and the precaution 

 necessary is either to earth the secondary circuit, which has, however, certain dis- 

 advantages, or to connect one or both of the leads to a safety appliance which 

 would automatically divert any excess current to earth, and at the same time shut 

 off the supply in that portion of the faulty circuit by the fusion of the lead wire or 

 mica-foils in the main cut-outs. 



The Cardew static arrangement, which has been adopted experimentally by the 

 London Electric Supply Company, and the vacuum protector designed by the 

 author, both effectually prevent any leakage from the primary to the secondary 

 circuit. Numerous experiments have been made with the last apparatus to ascer- 

 tain the distance which an alternating current of high E.M.F. will leap across the 

 two electrodes which were fixed in the' opposite ends of a glass tube from which 

 the air has been partially excluded. The results ditlered considerably from those 

 given by De la Rue in his experiments with a continuous current, and a phenomenon 

 was noticed, that the arc alter starting between the two points almost invariably 

 extended itself to a bow shape and ran back to the base of one or both of the 

 platinum electrodes, one of which nearly always fused, leaving that opposite 

 intact. 



2 



Printed in extenso in the Electrician, vol. xxiii. p. 577. 



Published in extenso in the Electrical Revieiv, September 20, 1889. 



