AMERICAN INSTITUTE. 467 



condary current was generated which gave a second flash, and so lengthened 

 out the impression given by the first flash. There is then an induced or 

 counter current produced by galvanic electricity which will account for the 

 delay. Faraday proved that there were sparks at both making and break- 

 ing connection. 



In our long telegraphs the wire, with its insulating coating, becomes an- 

 alogous to a leyden jar, giving an induced quantity current every time a 

 signal is transmitted. Such telegraphs are liable to many accidents — 

 leakage, burning of the wire, defective insulation, &c., &c. In the case of 

 the Atlantic cable, the constant expression from Valentia was, " Send signals 

 sharp," which proves that there was a difficulty in sending signals east- 

 ward. It may be possible, by and by, to employ cosmical electricity, and 

 so dispense with our expensive batteries. The upper portions of the atmos- 

 phere are charged with positive electricity, while the earth is negatively 

 charged ; our heads are in a region of positive, our feet in one of negative 

 electricity, and doubtless som.e one will employ these immense sources 

 of power, but who we know not. 



For submarine telegraphing perhaps it would be advantageous to employ 

 silver wires, as silver conducts better than copper. 



Dr. Vanderweyde. — Ten copper wires will cofiduct as well as eight 

 silver ones. The galvanic current acts differently in a helix from what it 

 does when in a straight wire. In one coil of the helix, the current produces 

 a secondary current in the coil next to it, and so on. The lenstheninw out 

 of the spark is due to the discharge of the secondary current. 



Some further remarks followed in irregular conversation, upon the pro- 

 bable ultimate success of the Atlantic telegraph, and the value of the tele- 

 graph in determining longitude, &c. The Association then adjourned, 

 having selected Steam Plowing as the subject for the next evening. 



Polytechnic Association of the American Institute, 



September 'iOth, 1859. 



Professor Mason, Chairman. John Johnson, Esq., Secretary, pro tern. 



The Chairman introduced the subject of the evening, by stating that the 

 measure of our ability to farm is our ability to plow, for with adequate 

 power for plowing, we could double the product of even the best cultivated 

 lands. The means employed in difl'erent ages and countries for turning 

 and pulverizing the soil, gives a good criterion by which to judge of the 

 civilization of a people. This subject — the employment of steamier some 

 other inanimate motor to do the heavy work of the farm — is deserving of 

 our best study and most careful investigation. Farm laborers are men. 

 They should be spared for lighter and more ennobling toil. 



Mr. Garvey being called upon, read the following paper on 



cultivation by steam power. 

 One of the great problems of the day is to find a method of apylying 

 steam power to the cultivation of the soil. ■ In the fall and early spring, 



