656 Transactions of the American Institute, 



iiig; and the warning which was repeatedly sent forth, but in vain, 

 through the sad fate of poor ballet girls, who had ventured too near 

 the foot-lights, will surely take effect now, when an auspicious alli- 

 ance has been set aside by the most miserable of accidents, and 

 when a lucifer match has proved even more adverse to the pacific 

 relatioiLs of two rival powers than the cannonade of Custozza, or 

 the heavy-shotted broadside of Lissa. 



Dr. Bradley said when a lady's dress takes fire, she should imme- 

 diately drop on the floor at full length, and endeavor to check the 

 flame by roUmg over; any other person present should immediately 

 cover the burning clothes with a carpet or woolen cloth. In this 

 way he had known of several lives being saved. 



wheatstone's new electric machine. 



This machine consists essentially of a bar of iron bent in horse- 

 shoe form, around which is coiled a covered copper wire, as in the 

 ordinary electro-magnet. Between the poles revolves a spindle, 

 carrying covered copper wire, insulated, but so arranged that either 

 end will be alternately brought into contact with each terminal of 

 the wire surrounding the iron bar. The spindle is so arranged that 

 during its revolution, on its long axis, it is made to present each 

 side in succession to either limb of the horse-shoe. An endless 

 band passes around the cii'cumference of a tolerably large fly-wheel, 

 and around the spindle, thus giving motion to the latter. When 

 the spindle is revolved rapidly the horse-shoe becomes magnetized, 

 a powerful electric current being induced in the Avire helix at the 

 same time; and as the motion is continued, the forces go on acting 

 and reacting until a ver}' high degree of intensit}^ is obtained. This 

 machine difl^ers from Mr. Wilde's in this respect, that in the latter 

 any body to be submitted to the action must form the termuials of 

 a complete circuit, whereas, in th'e Wheatstone machine, such a 

 body would form a bridge, or short cut, by which the electricity 

 completed its circuit. A small machine, turned by hand, is capable 

 of burning a piece of iron wire thirty inches long, and one-sixteenth 

 of an inch in diameter. A similar result is obtainetl by making 

 one terminal of iron wire approach the other terminal of copper 

 wire; the iron wire immediately takes fire and burns with a brilliant 

 corruscation. When the current passes between points of prepai-ed 

 charcoal, a beautiful and steady light is produced, showing that 

 an electric light of great brilliancy can be obtained on a small scale 

 with a relatively small expenditure of the power required to give 

 motion to the machine. 



