608 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



give an account of experiments in telegraphing which he had 

 made in 1837. He had put up a wire, tliree miles in length, in a 

 yard, crossing back and forth, and found that a single drop of 

 acid would act through the wire, the entire amount of the wire 

 being uninsulated. It had previously been supposed to be neces- 

 sary to wind it. He had tried various methods of recording, by 

 sand, by iron filings, and hy ink. 



The President remarked that the Chinese claim to have used 

 the magnetic needle as a means of guiding their wagons long 

 before they had any roads. It seemed remarkable that a power 

 so long known had never been made available for any other pur- 

 pose, excepting to find a protection against it in lightning rods, 

 than as a means of carrying messages. 



Mr. Bliss suggested that it was used medicinally. 



The President replied that it had not secured the assent of the 

 medical profession. 



Mr. Johnson said that electro-metallurgy was now taking a 

 very wide range in the arts. 



Mr. Holcomb said that the great difficulties in telegraphing 

 were the adjustment of the relay magnets ; and the interference 

 of other powers beside that of the battery, as electricity from 

 other sources. If some means could be devised to discharge the 

 induced electricity, or opposite electricity, from the outer coat- 

 ing of the wire, it would very much facilitate telegraphing. 

 These difficulties are so great and so variable that it is impracti- 

 cable to work with repeaters. For very long distances, it was 

 found to be necessary for some person to be continually adjusting 

 the relay magnets ; and the result had been that the repeaters 

 had been laid aside, and the messages were now repeated with 

 the fingers. 



Mr. Veeder suggested that if the action of the current is vibra- 

 tory, it would require liberty of the wire ; and there might there- 

 fore .be an advantage of passing the wire loosely through insula- 

 ting tubes at the poles. 



NEW STEAM BRAKE. 



Dr. Vander Weyde, in behalf of the inventor, exhibited draw- 

 ings of a brake for car- wheels,, to be operated by steam from the 

 locomotive, and capable of stopping the train within a distance 

 of sixty feet. Dr. V. remarked that, without having investigated 

 it, he should think it dangerous to apply such a brake. The 



