62 M. E. Stohrer on an Improved Induction Apparatus. 



taiued from 12 to 14 lines in lengthy whicli do not follow the 

 direct line joining the points, but sometimes describe consider- 

 able zigzag curves. Such long and rarely occurring sparks are, 

 however, only obtained when the lever C is pulled as strongly 

 as possible, so that the pi'essure of the platinum point on the 

 copper spring is very strong. When the points of the discharger 

 are caused to approach within about 8 lines of each other, 

 a continuous stream of sparks passes, which becomes more 

 intense when the jjlay of the interruptor is permitted to proceed 

 more quickly. The play of sparks at the discharger is very 

 beautiful when a bit of chalk, sugar, glass or wood is placed 

 between the points. Wood- shavings, paper, cotton-wool, and 

 gunpowder, are immediately ignited by the sparks. 



As these induced sparks develope a comparatively greater 

 amount of heat than those of the electric machine, even when 

 they proceed from the strongest battery, it may be expected that 

 such instruments will find application in the art of war, more 

 especially as preliminaiy experiments in France, with far feebler 

 apparatus, have already given satisfactory results. The igni- 

 tion of gunpowder, for example, is immediately effected when 

 Varrentrap's fuse is made use of. This fuse consists, as is known, 

 of a mixture of 2 parts of chlorate of potash and 1 part of 

 sulphide of antimony, and is spread over the gunpowder. If 

 through this mixture the smallest induction spark is permitted 

 to pass, it is immediately ignited. Six siich grenades, which 

 were connected one after another at great distances, I have com- 

 pletely and simultaneously ignited. The insulation for the in- 

 duced currents is far less difficult than for those of the electric 

 machine ; the apparatus itself is very small, not dependent on 

 the state of the atmosphere, &c. Of course, for practical pur- 

 poses, the instrument would be constructed in a totally different 

 and more simple manner than that just described. The inter- 

 ruptor, for exam]5le, would be formed of a single presser, similar 

 to the key of a Morse's telegraph. The induction coil and con- 

 denser could be so preserved in a box that injury would be im- 

 possible, as neither of them is fragile. This is not the place to 

 follow this purely technical subject further; it results, however, 

 from what has been said, that this electricity is more suitable 

 for the purpose mentioned than the frictioual electricity recently 

 applied in Austria. 



I partake less of the hope expressed by M. Sinsteden with regard 

 to the possible appKcation of induction currents for igniting the 

 coal-points for technical purposes. My apparatus ignites the 

 points very prettily. The coal is even rendered glowing ; but 

 the intermittent character alone of the induced ciu'rent" would 

 deter me from further experiments, for such a Ughf could never 



