554 transactions op the american institute. 



Electricity and Magnetism. 



This subject, continued from the last meeting, was here resumed. 



The Chairman. — I noticed an article in the Tribune a few days ago in re- 

 lation to an improvement in electro- magnetism, in which expectations were 

 expressed by the editor that steam would be superceded by electricity; but 

 when we reflect that power generated by electro-magnetism, has been esti- 

 mated to cost about fifty times that of steam, and that Dr. Page, of Wash- 

 ington, admitted that by the use of his electro-motive engine it could be 

 reduced to a cost only to twenty times that of steam,* it will be seen how 

 unfounded such expectations are. Electricity is generated by the com- 

 bustion of metals; for instance, oxygen unites with zinc and electric force 

 is given off. If we compare the cost of zinc the cheapest positive metal 

 used, and of coal, we will find a vast difference in favor of the heat-force 

 generated by coal. 



Mr. George Bartlett. — Mr. Beardsley's invention alluded to by the chair- 

 man, consists in a modified form of magnet, which he makes in a star 

 shape, which amounts to the same thing as 3 U magnets of cast ii'on. 

 These he makes of various sizes, and tlien a larger one is placed over these 

 which are then put on a shaft and made to revolve by macliinery — and in 

 this way he produces his electro-magnetism. Recently he has applied this 

 principle to the telegraph as it dispenses with a battery. He lias an al- 

 phabet placed around a circle, and by turning the magnets, the electricity 

 is made to turn this circular disc until a certain letter is arrived at, after 

 which a brief pause is made and goes on to the next letter. This is so 

 arranged that a person can read the words without anj'- previous training. 

 One very curious optical illusion was produced b}' this process. The mag- 

 nets were turned round and the current was so arranged as to be broken, 

 and the flashes of light were so bright that they seemed to be going in an 

 opposite direction. 



Mr. B. Garvey. — A device for producing signals which I saw in England 

 several years ago, was in a disc form with a hand made to stand perpen- 

 dicular, a horseshoe magnet drew the armature which started some clock 

 work, and when the hand came to a certain letter the current was broken, 

 after which the hand was set in motion until the next letter required was 

 pointed at. This has now been abandoned as the mode of signalling by 

 making dots into a piece of paper, or by alternations of long and short 

 sounds gives all the letters required. 



Tiie Chairman. — The Morse telegraph is now, after a lapse of about 

 twenty years, since its perfection, used throughout Europe, except in Great 

 Britain, where the monopoly granted to Cook and Wheatstone, fur the ex- 

 clusive use of electricity for telegraphic purposes, still exists. The Cook 

 and Wheatstone instrument hardly deserves the name of an invention. It 

 was invented or proposed by Ampere in the year 1822. It is simply a mo- 

 dification of the old galvanometer needle, consisting of two or more needles, 

 which by their various positions, made by the magnetic current, indicated 

 the letters of the alphabet. At first five wires were reqiiired for each line 

 It is a sight telegraph, and must be constantly wajched when messages are 

 being communicated. The vast telegraphic business of this country could 



