RECENT ADVANCES IN ELECTRIC LIGHTING. 381 



street lamp-j^osts, one machine working many lights. The foi*mer 

 system appears to be the best for symmetrical spaces and large areas, 

 the latter for long and narrow streets and thoroughfares ; so, in inter- 

 nal illumination, the central system is preferable for lofty, spacious 

 rooms, the distributed for long and low ones. 



An eventful feature in practical lighting is the proper scattering or 

 diffusion of light, by shades, screens, and reflecting surfaces. We want 

 to emulate the diffusion of daylight. It is marvelous how white- 

 washed surfaces do this. Well-selected globes act as though they 

 were self-luminous ; they scatter light and produce shadows. The 

 power of the light, however, to penetrate fogs does not appear to be 

 any greater than that of gaslight. This is because the shorter-waved 

 rays that give the light its violet tint are checked by the vapors, in the 

 same manner as the like rays in the sun are checked, and it is made to 

 appear red. The same cause operates to give the electric light a 

 greater illuminating power in its immediate neighborhood, for the 

 checked rays are reflected back to add their intensity to that of the 

 direct rays. 



Xearly three hundred Gramme machines are in use in England 

 generating light ; there are many more Siemens machines, and the 

 Brush people have installed many machines and lights. Xearly all the 

 ironclads in the navy are supplied with the electric light. In libraries, 

 while reading by gaslight is irksome, reading by the electric light is 

 simply delightful. Railway-stations are gradually adopting the lights ; 

 seaside resorts are illuminating their parades with them. It would be 

 impossible to make any summary of the numerous manufacturing es- 

 tablishments that have been supplied with lights worked successfully. 



Notwithstanding these great advances in its use, it must not be for- 

 gotten that the electric light has its defects and its disadvantages. The 

 intense shadows that it occasions are troublesome. The unsteadiness 

 of the light is at times wearisome. The hissing which impurities in the 

 carbon and irregularities in the current produce is tantalizing, and the 

 lio-ht has an unfortunate habit of misbehavinsr itself when it is most 

 wanted. Moreover, the problem of durability remains yet to be solved. 

 Many have tried the light and abandoned it. In some cases its econ- 

 omy is unquestionable, but there are places where careful persons 

 have shown that gas, as regards economy, surpasses it. It is question- 

 able whether, in some cases, the electric light does not affect the eye. 

 The arc-light produces, also, nitrous acid and other deleterious gases, 

 but the incandescent lamp is free from this trouble. The powerful 

 currents that it requires can not be carried over buildings and rooms 

 without incurring danger from fire and to life. Xevertheless, the light 

 has great and manifold advantages. The brilliancy of a well-lighted 

 room is simply enchanting. The purity of the light for the transaction 

 of business, the selection of colors, and the ordinary daily avocations of 

 life, is simply superb. Its cleanliness is one of its great merits. It 



