192 ELECTRIC LIGHTING. 



body of the lamp are connected by a tube, at one part of 

 which is a circular opening stopped by an extensible mem- 

 brane, and above this membrane a kind of plug is applied 

 controlled by the armature of an electro-magnet, which, as 

 in the foregoing system, stops or allows the flow of the liquid 

 according to the greater or less intensity of the current. 



In Way's lamp, which was much talked about in 1856, 

 and which moreover caused its inventor's death, the carbons 

 between which the voltaic arc is generally produced were 

 replaced by a tine stream of mercury issuing from a small 

 funnel and received into an iron basin also containing mer- 

 cury. The two poles of the generator being connected, one 

 with the funnel and the other with the basin, a series of 

 voltaic arcs were produced between the successive drops of 

 the discontinuous stream, and the combination of these arcs 

 formed a source of light tolerably brilliant and uniform. The 

 luminous vein was enclosed by a glass tube sufficiently narrow 

 to become so hot that the mercury should not condense, on its 

 surface ; and as the action took place out of contact with 

 oxygen, the mercury was not oxidized. Way modified this 

 first arrangement by using two jets of mercury instead of a 

 single one, and these jets were so arranged that they met 

 together at one point, from which they flowed on in drops. 

 He also closed and interrupted the currents continually by 

 means of a small electro-motor set in motion by the battery, 

 and which drove the mercury pump that supplied the jets. 

 But in spite of these improvements, it was necessary to 

 abandon this apparatus on account of the mercurial vapours 

 that escaped from it, and which at length killed the inventor. 

 Moreover, the light attained to little more than a third of 

 that produced by the same current between two carbon 

 points. 



As a special form of arc lamp, I must say a few words 

 about J. Van Malderen's regulator, which is based upon the 

 repulsions between the contiguous elements of one and the 

 same current. It is a kind of suspended compass, the 



