4 3o THE POPULAR SCIENCE MONTHLY. 



dying of cholera. In the first instance, it appears that the body is fully 

 charged with its own electricity, since it is impossible to electrify a 

 body beyond a certain degree ; in the latter, there seems to be a ten- 

 dency to part with the electrical force which is essential to the support 

 of life, and which may account for the distressing and rapid weakness 

 of cholera patients. 



We have hitherto spoken only of electricity of very high tension, 

 which produces the lightning-spark ; and which boys and girls know 

 as the product of the frictional electrical machine, the shock of which 

 their elbow-joints constantly remember. We wish now to refer to 

 something infinitely more quiet and peaceful, and to which we are 

 indebted for many of our greatest luxuries. 



Galvani's boy-pupil, amusing himself in his master's laboratory, 

 accidentally bringing the legs of a recently-killed frog into an electric 

 current, the great philosopher perceived at once the manifestation of a 

 new power. It remained only for Volta to invent his pile, consisting 

 of a continued series of zinc and copper plates, with pieces of cloth 

 between, and the foundation and general principles of electro-galvan- 

 ism and voltaic electricity were laid down. 



Frictional electricity has been compared to the high-pressure steam 

 of a locomotive, and voltaic electricity to the steam rising quietly 

 from an open boiler. The chemical action of frictional electricity is 

 very feeble; it has great intensity but little quantity; while the vol- 

 taic pile will yield an enormous quantity of electricity but with feeble 

 intensity. Faraday calculated that it would require a Leyden battery 

 to be charged by 800,000 turns of a powerful plate machine to decom- 

 pose a single grain of water, which by one of Pulvermacher's bands 

 may be done in a few seconds. 



It is to this latter agent, voltaic electricity, that we are indebted 

 for electroplate, which has not only rendered our tables more decent, 

 but has supplied real works of art, and statues and ornaments innu- 

 merable. That is also the power by which we are enabled to convey 

 our thoughts thousands and thousands of miles, over mountains and 

 through vast oceans, and to converse from our dining-room with our 

 friends in almost every part of the world ; while by its agency rocks 

 are blasted, cannons and torpedoes are fired, and even the bells of 

 some of our houses are run**. 



Undoubtedly, however, the greatest marvels of this beneficent 

 agent are to be fc4md in its influence on the human frame, and in the 

 cure of disease. But, like every thing that is destined eventually to 

 be accepted by the public as a matter of course, it has had to pass 

 +hrough the usual three stages of contempt, controversy, and adop- 

 tion. More than a hundred years ago John Wesley said : " How 

 much sickness and pain may be prevented or removed, and how many 

 lives saved, by this unparalleled remedy ! And yet with what vehe- 

 mence has it been opposed ! Sometimes by treating it with contempt, 



