and other Substances by Electricity. 25 



When four such jars were charged to the highest possible 

 intensity, and discharged through the water tul)e,— gold leaf 

 placed in the circuit was powerfully attracted, but not defla- 

 grated. 



One jar with an intensity of 60°, powerfully magnetized a 

 sewing needle, placed in a spiral forming part of a complete 

 metallic circuit. With twojars charged to the highest possible 

 intensity, no magnetic effect was produced, when the tube of 

 water formed a part of the circuit. 



How do these experiments accord with the doctrine o^ quan- 

 tity and intensity? In the galvanic process, a needle may be 

 powerfully magnetized by a single pair of small copper and 

 zinc plates ; by which process, it is said, we have quantity, 

 but not intensity. But by the experiments I have just now 

 mentioned, it appears that quantity has not the power of mag- 

 netizing needles, without intensity. For when the electric fluid 

 was not retarded by inferior conductors, a very small quantity 

 produced the effect ; but when the ?W^«5% of the discharge 

 was reduced, although three times the former quantity, at 

 least, was employed, not the slightest magnetic effect was pro- 

 duced. The truth is, we want another and a more appro- 

 priate term in electricity ; — that term is Momentum. Intensity 

 answers very well to express the relative degrees of concen- 

 tration on the surface of jars, &c., but momentum is the proper 

 term when the fluid is in motion. Hence then, although the 

 less quantity of fluid produced on the needle an effect which 

 the greater was unable to accomplish ; this effect was proba- 

 bly owing to the momentum of the former exceeding that of 

 the latter. • 



When tow or cotton is moistened with spirit of turpentine, 

 or mixed with powdered resin, it will ignite by a very small 

 electrical discharge when the whole circuit is of metal. But if 

 the tube of water form a part of the circuit, the tow, or cotton, 

 prepared as above, will not ignite, althougli two of the before- 

 mentioned jars charged to the highest possible intensity be dis- 

 charged through the circuit. 



When a narrow slip of gold leaf was placed between two 

 pieces of glass, and made to form a part of a complete metal- 

 lic circuit ; one jar with an intensity of 80° discharged through 

 that circuit, completely exploded the gold leaf When twojars 

 were employed at the same time, and charged to a still higher 

 intensity than the former, and the water tube entered into 

 the circuit; a similar slip of gold leaf subjected to the dis- 

 charge, remained uninjured. 



When gold leaf anil gunpowder were subjected at the same 

 time to a discharge similar to liie above, and the whole cir- 



Nexv Series. Vol. 1. No. ].Ja/i. 1827. E cuit 



