112 ANNUAL OP SCIENTIFIC DISCOVERY. 



liant and desirable light ; but so much difficulty has been heretofore 

 experienced in securing the proper relative positions of the pencils, 

 and in keeping them pointed, that electricians have been forced to 

 very ingenious, but expensive and often complicated, mechanical 

 appliances to obviate these the only apparent objections to the use of 

 the desired carbon electrodes. 



Any one who has examined the complicated mechanism of former 

 electric lamps must be struck with the remarkable simplicity and 

 perfection of the apparatus originated and constructed by the Messrs. 

 Collier & Baker, which secures most accurately the adjustment of the 

 carbon points. Dispensing with all gearing, springs, screws, electro- 

 magnetic regulators, or other complications, its simplicity is only 

 equalled by an ordinary candlestick, and its appearance is about as 



unassuming. 



The main feature of this lamp is a hole in a metallic strap or 

 bridge, which secures the position of the points, and regulates the feed 

 or supply as fast as consumed. The carbon pencils being in vertical 

 positions, the upper one is fed down by gravity, and the lower one as 

 a float is fed up by its own buoyancy. The hole or orifice in the upper 

 metallic strap or bridge is of a diameter a little less than the body of 

 the pencil, so as to permit a portion only of the point to pass through, 

 and as fast as it is reduced in size by the oxidation and disengage- 

 ment of particles during the process of combustion. The pencil is 

 thus gradually and surely fed downwards, and the feed regulated and 

 controlled by its own combustion. 



Using an electric current of large volume and low intensity, as the 

 Messrs. Collier & Baker much prefer, the electrodes may remain in 

 contact ; then the hole in the lower strap, being the same size as the 

 body of the lower pencil, acts as a perfect guide to the pencil as it 

 passes up through it, and the lower pencil, resting its point against 

 the point of the upper pencil, is thereby controlled in its feed upwards. 

 Using a current of high intensity, it being desirable to separate the 

 points and maintain that distance, the feed of the lower pencil is 

 regulated and controlled by reducing the size of the hole in the strap 

 to correspond with the upper one, and for the same purpose, using a 

 current of electricity constant in one direction, there is a tendency to 

 an accumulation of particles of carbon on the negative electrode, 

 and a consequent blunting of that point. To avoid this, Messrs. C. 

 & B. use a to-and-fro current. In this invention, the extremes of 

 simplicity and cheapness are combined, the cost of the lamp being 

 but a few dollars. 



There can be little doubt, adds Mr. Fleury, but that the applica- 

 tion of magneto-electric machines for the production of light, and for 

 all purposes where a large amount of electricity is required, will soon 

 supersede the use of galvanic batteries. A few words relative to the 

 importance of this machine for the ordinary telegraph may here not 

 be amiss : 



The extent of telegraphs in the United States is increasing every 

 day ; the capital involved is upwards of six millions of dollars. To 

 work the telegraph lines, it, takes annually 720 tons zinc, worth $60,- 

 000; more than 1,000,000 pounds nitric acid, worth $120,000; and 

 $30,000 worth of mercury ; besides a considerable amount of sulphu- 



