Electric Lighting. 101 



graph appears : — " Can electricity be distributed as widely 

 and cheaply as gas ? On one condition, which I hope can 

 be complied with, this may be answered in the affirmative. 

 The condition is that it be found practicable and safe to dis- 

 tribute electricity of comparatively high tension." 



It will thus be seen that Mr. Swan assumes that a high- 

 tension current is absolutely necessary for an extended and 

 economic distribution of the current, and with our present 

 method of working, there is very little doubt that his views 

 are correct. I am, however, of opinion that, instead of en- 

 deavouring to perfect any system which requires for its suc- 

 cess the employment of such currents, we should turn our 

 attention to obtain the required results by the safe and 

 easily worked low-tension current. 



Respecting arc lamps, I have little to add to my former 

 remarks. Their construction has been considerably simpli- 

 fied, and by this means several difficulties formerly ex- 

 perienced in their working have been removed. 



The specimens before you this evening are the " Siemen" 

 pendulum and differential lamp, fitted with Dr. Siemen's 

 abutment pole, for burning from fourteen to nineteen hours ; 

 the " Brush," double rod, burning sixteen hours ; and the 

 " Weston" lamp, slightly modified and manufactured in the 

 colony. The last two lamps contain no wheel work or 

 delicate mechanism to feed the carbons, the regulation being 

 effected solely by electro-magnets so arranged that the 

 proper length of arc is maintained by means of a shunt of 

 fine wire placed in circuit between the two carbons, and 

 acting in an opposite direction to the main wire coils. The 

 arc lio-ht remains as before the most economical means of 

 illumination for large spaces, a light of about 3000 candle- 

 power being maintained by an efficient dynamo-machine, 

 and driven by a gas-engine consuming about sixty feet of 

 gas per hour, or as much as would suffice for the support of 

 from twelve to fifteen gas-jets for the same period, and when 

 it is borne in mind that gas costs three times as much as 

 coal for an equivalent amount of power, the economy of the 

 arc light becomes at once apparent. The Jablochkoff candles 

 still maintain a prominent position in electric lighting on the 

 Continent; but beyond lighting part of the Thames embank- 

 ment, London, the system does not appear to have made 

 much progress in England. Semi-incandescent lamps also 

 do not make very much headway. One that has been 

 prominently before the public for some time is the Joel 



