Miscellaneous Notices on Galvanic Results. 35 



having been repeated, a powerful horse-shoe magnet was held 

 horizontally with its north or marked end uppermost ; the wire 

 from the negative end of the battery was firmly pressed upon 

 the magnet, and the positive wire brought to within the striking 

 distance, when we had the pleasing satisfaction to observe a brill- 

 iant circular flame of electrical light, revolving from left to right, 

 as the hands of a watch. When the position of the magnet was 

 reversed, and the effect obtained from the south or unmarked end 

 of the magnet, the flame revolved from right to left. The ap- 

 pearance of the flame was not unlike that of the brush from an 

 electrical machine received on a large surface, only much more 

 brilliant." 



Conclusion. — The following remarks, in answer to enquiries 

 made of Mr. Sturgeon as to his views regarding the best forms of 

 galvanic batteries, are worth preserving, as the conclusions of so 

 experienced an experimenter, and the more so as they coincide 

 generally with the views of Dr. Hare, and of other distinguish- 

 ed men in this country. — Eds. 



Form and size of Galvanic Batteries. 



" With respect to galvanic batteries, we can never expect to find 

 07ie which will exhibit every class of phenomena to the best ad- 

 vantage. The pile, with moistened card board in pure water, or 

 a well constructed Cruickshank, charged with water, answers 

 best for charging Leyden jars, deflections of pith balls, &c. And 

 the more extensive the series the better. The size of the plates 

 has also much to do in this business. A single pair of plates, 

 charged with dilute nitrous acid, answers best for most electro- 

 magnetic experiments. For a display of brilliant calorific phe- 

 nomena, the burning of charcoal, deflagration of laminated metals, 

 &c., a series of not less than a hundred pairs answers better than 

 any smaller series. Here again, the size of the plates should 

 never be less than four inches square. Six inch plates answer 

 much better, and two hundred better than one hundred, &c. And 

 these may be either of the Cruickshank form, or of any other, 

 observing that the action with the former is of much shorter du- 

 ration than with the Wollaston form, and shorter with the Wol- 

 laston than with the battery of jars before described. 



" Then again, for heating of thick wires, a series of ten or less, 

 of large plates, are better than more extensive series. 



