1880.] Louis Scliwendler — On the Employment of, Sfe. 



167 



XVII. — On some Experiments instituted to supply all the Lines termi- 

 nating at the Galcutta Telegraph Office with Currents tapped 

 from the Ifain-Ctirrent produced by a Dynamo-electric Machine.* 

 — By LOTTIS SCHWENDLEB, M. Iiisfc. C. E. 



Introduction. — Oa the 5fch November 1879, I had the honour to read 

 a short paper before this Society entitled, f " Ou a simple Method of 

 using an insignificant Fraction of- the Main-Current produced by a 

 Dynamo-Electric Machine for Telegraphic Purposes." 



In the present paper, I wish to record some more experiments on the 

 same subject. As stated in my former paper, tlie dynamo-electric machine, 

 during this first experiment, was placed at the store-yard, and was driven 

 by the steam engine of that place. The telegraph current was conveyed 

 to the Calcutta Telegraph Office by the store-yard line, which is about 

 4 miles in length. This first trial proved so successful that I ventured to 

 propose a larger trial to supply all the lines entering the Calcutta Telegraph 

 Office with signalling currents derived in this manner. But I could not 

 then execute the new trial, as in the first place there were no proper driving 

 arrangements at the store-yai'd (the erection of these would have cost 

 money), and in the second place the dynamo-electric machine at my disposal 

 had, by an accident, been temporarily spoiled. It was thought advisable, 

 therefore, to postpone the suggested trial on a larger scale until the electric 

 light arrangements at HowrahJ should be completed, when an easy oppor- 

 tunity would offer itself for trying different dynamo-electric machines for 

 the purpose. Besides, telegraph lines being already up between the Howrah 

 Railway Station and the Calcutta Telegraph Office, no additional expense 

 would need to be incurred. 



iVt'iy trial on a larger scale. — The preliminary trial was instituted on 

 the 28th August, the final one on Sunday the 29th August 1880. 



In the accompanying diagram, M is the dynamo-electric machine 

 which produces the main current to be made use of for any required 

 25urpose ; the negative pole of tlie dynamo-electric machine is connected 



* The results given in this paper are taken from" my report submitted to the 

 Director General of Telegraphs in India on the 7th September 1880. 



t J. A. S. B., Vol. xli.\, part ii, 1880, and Phil. Mag. No. 52. Suppl., Decem- 

 ber 1879. 



X Mr. Bradford Leslie, Agent of the East Indian Eailway Companj', gave me 

 permission to use the electric light arrangements at Howrah for the purpose. He 

 also kindly permitted tlie use of the telegraph line connecting his oiBce at Calcutta 

 with the Railway Station at Ilownih. This line was required to give orders duiing 

 the experiment. 

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