140 ANNUAL OF SCIENTIFIC DISCOVERY. 



tional adhesion. Before doing so, however, I carefully inquired of those 

 most likely to be informed, both in this country and in Europe, if previously 

 ascertained facts indicated the probability of success, and I was almost dis- 

 couraged by the unanimous answer, " Xo." But I persevered, and the result 

 is more than was anticipated. An additional adhesion of over seventy-five 

 per cent, has been obtained, and this by a very simple method. 



The lower segment of the wheel is surrounded by a helix of copper wire, 

 through which the wheel revolves; and, contrary to the generally received 

 opinions, it was found that, upon curving the helix into a segment, the ra- 

 dius of which is equal to the diameter of the wheel, the point of greatest 

 magnetic effect coincided with the contact of the wheel and rail. One wheel 

 had south polarity, and its corresponding opposite wheel north polarity. 

 The wheels magnetized in the experimental trial were 4j feet in diameter, 

 and weighed about 1100 Ibs. each. On a very slippery rail, 19 Ibs. of steam 

 per inch slipped the wheels without magnetism ; under the same condition, 

 3-3 Ibs. were required to slip them when magnetized. On a very clean rail, 

 and everything being favorable, 50 Ibs. were required without any magnetic 

 effect, and 88 Ibs. Avhcn magnetized. The helix was made of No. 8 copper 

 wire, in one strand, 2700 feet in length, and laid in 288 turns, insulated with 

 cotton and marine glue, and covered with India-rubber. I have not been 

 able to discover any increased or diminished effect by the wheels being in 

 motion or at rest, and they Avere tested up to 300 revolutions per minute. 

 The battery used was a modification of Grove's, so contrived as not to stop, 

 and consisted of sixteen cups each, having about 300 inches of zinc surface, 

 and they were connected for the quantity of eight cups. 



I have since adopted a modification of Smee's and Chester's battery, being 

 more permanent. It should be noticed, that when the helices produced the 

 greatest effect, they were raised about 2 inches above the rail, measuring 

 from their under sides. 



TELEGRAPH APPLIED TO MILITARY PURPOSES. 



At the battle of Solfcrino, a high degree of precision in evolution was at- 

 tained by the French army, by means of the telegraph. 



From each corps, once in position, a horseman rode off to the next divis- 

 ion, unrolling on his rapid course a light wire, which no time was lost in 

 adapting to a field apparatus; and the process was repeated all along the 

 French line of twelve miles. Hence the movement of the whole army was 

 known and regulated like clock-work, on that decisive day. This arrange- 

 ment had been planned in Paris, and a supply of gutta-percha covered metal 

 thread forwarded with secrecy and dispatch. 



MAGNETIC ACTION OF THE SUN. 



The following abstract of a lecture delivered before the Royal Institution 

 (London )j by Mr. Brayley, exhibits in brief the present state of our knowl- 

 edge respecting the magnetic action of the Sun, and its connection with the 

 spots on its surface, the earth's magnetism, and the polar lights, or the re- 

 sult of those observations by which, as it has been said, we are "landed in a 

 system of cosmical relations, in which both the sun and the earth, and prob- 

 ably the whole planetary system, are implicated." In the opinion of the 

 Joint Magnetic Committee of the British Association for the Advancement 

 of Science, and the Royal Society, expressed in their report, that discussion 



