NATUEAL PHILOSOPHY. 145 



a very simple combination and arrangement of the two systems of House and 

 Morse, from two to twenty-eight messages might be in the process of transmis- 

 sion over the same wire at one and the same time. Thus : Suppose we have two 

 letter-printing telegraphs, one situated hi Boston, the other in New York, and 

 connected as usual for the purpose of transmitting messages ; suppose, further, 

 that the axis of the type-wheel in the Boston machine was connected by a 

 wire with one pole of a suitable galvanic battery, while the other pole of this 

 battery was connected by an extended wire with the axis of the type-wheel 

 of the machine in New York ; further, let us remove the two type-wheels from 

 their axis and substitute therefore a slender spring on each, at right angles to 

 the axes, and which in the course of a revolution of the shafts shah 1 make 

 contact with the twenty-eight circular segments arranged concentrically 

 around the axis of the type- wheel and insulated from it and from one another ; 

 still further, let each of the twenty-eight segments in the Boston instrument 

 be connected severally with one pole of a complete " Morse" machine, which 

 is, at the other pole, in connection with the earth ; there will then bo 

 twenty-eight " Morse" machines at Boston attached to the " House" machine, 

 and by the revolution of the type-wheel axis these twenty-eight machines will 

 be successively put into connection with the common communicating wire. 

 Suppose twenty-eight " Morse" machines similarly connected with the "House" 

 machine at New York ; if now the slender spring in each " House" machine 

 presses on the " A" segment and the two type-wheel shafts be made to rotate 

 rapidly in the usual manner, at every revolution of the type- wheels the "A" 

 machines at Boston and New York will be at once in connection with each 

 other by means of the slender springs, the segments, and the common wire. 

 If the type-wheels should make twenty revolutions per second, the dots or im- 

 pulses would succeed each other so rapidly as to make nearly a continuous 

 line, which could be broken up into short and long lines by means of the key 

 in the usual manner. He had operated with this arrangement on a circuit of 

 several miles in length at Boston. 



TilPEOVEilEXT IN ELECTROTTPIXG. 



TThen a page of type, or a wood engraving, is to be duplicated by the elec- 

 trotype process, an impression of the article to be reproduced, is taken in soft 

 beeswax. The mold thus made is dusted over with finely ground plumbago, 

 and then placed in a solution of sulphate of copper, where it is subjected to 

 the galvanic battery. The plumbago serves as a metallic base, on which cop- 

 per is deposited in the same manner that substances composed wholly of metal 

 are coated or galvanized. The dusting of the wax molds has heretofore been 

 done by hand, which is a slow and laborious operation ; it is also imperfect, 

 for unless great care is taken to dust every portion evenly, the electrotype 

 will prove defective. An improvement has been recently patented by Mr. J. 

 A. Adams, of Brooklyn, N. Y., for accomplishing this dusting wholly by the 

 aid of a vibrating brush, combined with a carriage-way, thus performing the 

 work more perfectly and economically than before. 



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