NATURAL PHILOSOPHY. 129 



inches, presenting- by far the most powerful magnet ever known. 

 When the circuit with the helix is suddenly broken, a secondary 

 spark is produced eight inches in length. The most interesting fea- 

 ture of this spark is the modification of its form and sound by the ac- 

 tion of magnetism. When the spark is produced at a distance from 

 the magnet, it is readily elongated to six or eight inches, and I pre- 

 sume might be obtained a foot or more in length if the wires were 

 separated with the velocity of a cannon-ball. In this case there is 

 little or no noise made by the spark, but as the spark is produced 

 nearer to the magnetic pole the sound increases, until at last, when 

 close to the pole, each spark makes a report as loud as a pistol. The 

 spark also diminishes in length, and is spread out as large as the palm 

 of the hand. There is an effect here somewhat analogous to that pro- 

 duced by a magnet upon the arc of flame between charcoal points. 

 Prof. Charles G. Page, Silliman's Journal, Nov. 



CURIOUS ELECTRICAL PHENOMENA. 



PROF. LOOMIS described to the American Association at New Ha- 

 ven some curious electrical phenomena observed in certain houses. 

 " Within the past two years, several houses in the city of New York 

 have exhibited electrical phenomena in a very remarkable degree. 

 For months in succession, they have emitted sparks of considerable 

 intensity, accompanied by a loud snap. A stranger, upon entering 

 one of these electrical houses, in attempting to shake hands with the 

 inmates, receives a shock, which is quite noticeable and somewhat 

 unpleasant. Ladies, in attempting to kiss each other, are saluted by 

 a spark. A spark is perceived whenever the hand is brought near to 

 the knob of a door, the gilded frame of a mirror, the gas pipes, or 

 any metallic body, especially when this body communicates freely 

 with the earth. In one house, which I have had the opportunity to 

 examine, a child, in taking hold of the knob of a door, received so 

 severe a shock that it ran off in great fright. The lady of the house, 

 in approaching the speaking-tube to give orders to the servants, re- 

 ceived a very unpleasant shock in the mouth, and was very much 

 annoyed by the electricity, until she learned first to touch the tube 

 with her ringer. In passing from one parlour to the other, if she 

 chanced to step upon the brass plate which served as a slide for the 

 folding-doors, she received an unpleasant shock in the foot. When 

 she touched her finger to the chandelier there appeared a brilliant 

 spark and a snap. After a careful examination of several cases of 

 this kind, I have come to the conclusion that the electricity is created 

 by the friction of the shoes of the inmates upon the carpets of the 

 house. I have found, by direct experiment, that electricity is excited 

 by the friction of leather upon woollen cloth. It may be thought re- 

 markable that the electricity should be intense enough to give a bright 

 spark. In order to produce this effect, there must be a combination 

 of several favorable circumstances. The carpet, or at least its upper 

 surface, must be entirely of wool, and of a close texture, in order to 

 furnish an abundance of electricity. So far as I have had opportunity 



