ASIMAI ELECTRICITY.] UNDULATORY FORCES. ELE CTRO-METALLTJRGY. 



197 



the contortions of the face, and the contractions of 

 various muscles so produced, were of such a horrible 

 character, that most of the spectators had to leave the 

 room from sickness or faintness. Such experiments 

 may easily be repeated on rabbits, cats, and dogs, imme- 

 diately after death. In one experiment which we tried 

 by a powerful battery, a rabbit leaped several feet from 

 the table on which it was placed, which was caused by 

 the powerful contraction of the muscles of the leg. By 

 a judicious insertion of the poles of the battery in 

 different parts of the body, any set of muscles may be 

 called into play, and the effects almost invariably pre- 

 sent the appearance of restored life in the subject. 



ANIMAL ELECTRICITY. 



IN the previous chapter, we confined our remarks on 

 this subject to describing some particulars in reference 

 to electrical fishes. We shall now place before our 

 readers gome facts relating to the effects on, and the 

 production in, the bodies of animals, of free electricity. 



Electricity and magnetism have always been charged 

 with being the cause of various phenomena observed in 

 animals, to which no other could be assigned : hence, we 

 have had the vagaries and absurdities of "mesmerism" 

 and " animal magnetism" continually thrust on public 

 notice. We can only spare space to remark, that those 

 who have been most prominent in support of such sub- 

 iects, have generally been equally eminent for their 

 ignorance of true science, and have, according to the old 

 adage, found plenty to admire them. It Is a most un- 

 fortunate failing of our mental powers, when in an 

 untrained state, that we are always ready to believe 

 that which is hardly credible, in preference to well-sub- 

 stantiated facts and conclusions which may be readily 

 driiionstratc'l the imagination frequently overruling the 

 power of our reasoning faculties. 



It has long been known, that electrical may, in some 

 caws, be substituted for nervous action ; and thus, 

 many years ago, it was shown that a piece of zinc, and 

 one of platina, might be inserted between the previously 

 divided nerves of the stomach of a rabbit, and that 

 digestion, and other vital processes, continued just as if 

 no alteration of the continuity of the nerves had 

 occurred. 



AMiiii has made numerous researches in this branch of 

 science ; and the fact of free electricity in the current form 

 Ix.-ing always present in the body, and passing between 

 the nerves and muscles, has been satisfactorily proved. 

 Indeed, a voltaic battery may be made, and many expe- 

 riments can be tried, by means of the nerve and muscle 

 recently obtained from the living animal, if such are 

 arranged in a similar form to that of the voltaic pile.* 



Many persons may exhibit a kind of double set of 

 phenomena in reference to electricity. Some, indeed, 



may have the hair and skin excited by friction, so as to 

 afford sparks in abundance. This, however, is chiefly 

 observed in persons of a phlegmatic temperament, having 

 a harsh skin, and a freedom from excessive perspiration 

 of the body. Others, of a sanguine and nervous tem- 

 perament, more readily exhibit free electricity in the 

 nervous system, arising, as far as we know, from chemi- 

 cal action. Thus we may rank individuals under the 

 separate classes of those presenting the phenomena of 

 frictional and voltaic electricity respectively. 



That electricity has a decided influence on the general 

 health, is admitted on all hands. Every one experiences 

 in foggy weather, or at times when the atmosphere is 

 surcharged with electricity, a peculiar heavy and de- 

 pressed feeling. The sanitary tables, now so freely 

 published, when taken in connection with simultaneous 

 electrical observations, indicate that electricity has a 

 definite relationship, in some way or another, with the 

 health and diseases of a community. 



This fact, however, has been sometimes extended far 

 beyond its legitimate limits ; and there have been those 

 having some claim to a scientific reputation, who have 

 not hesitated to avow their belief that electricity is the 

 vital principle. Had they affirmed the same of caloric, 

 their views would have had a more feasible or plausible 

 appearance ; for it is an admitted fact, that life cannot 

 be maintained unless a certain amount of animal heat is 

 kept up. It is, however, unnecessary for us to discuss 

 this question. The common sense and experience of our 

 daily lives, apart from the more exact teachings of sci- 

 ence, are sufficient to show, that however active ant' 

 necessary certain agents may be for the purpose of pro- 

 ducing definite results, it by no means follows that such 

 are primary causes. The celebrated Stephenson once 

 asked a friend what it was that caused the rapid motion 

 of one of his locomotives. The reply was characteristic 

 of an experimentalist the combustion of the fuel in the 

 furnace was assigned as the reason. Stephenson, how- 

 ever, most expressively corrected this ; and referred to 

 the fact, that all the heat and effect produced, were due 

 to those rays of heat and light which had first IK i u 

 absorlxxl from the sun, and were given out again with 

 their full force in the furnace; although, perhaps for 

 thousands of years, they had laid dormant in the bowels 

 of the earth. In the same spirit, the true philosopher, 

 whilst investigating and admiring the chain of second 

 causes, constantly operating in the course of natural 

 phenomena, refers all for their first origin, to that Great 

 First Cause who called them into being. As glimpse 

 after glimpse is obtained of the infinity of creative 

 power, which our limited intelligence can but feebly 

 comprehend the humble but earnest inquirer is com- 

 pelled, in reverence, to exclaim "Oh Lord, how mani- 

 fold are thy works; iu wisdom hast thou made them 

 all" 



CHAPTER III. 

 ELECTRO-METALLURGY. 



Tun following paper, written by Mr. Gore, of Birming- 

 ham, affords full details of the theory and practice of the 

 arts of electrotyping, gilding, plating, <tc. As many of 

 the subjects which were discussed in the original, have 

 iily been mentioned in the preceding pages, the 

 editor has omitted such portions, and has made various 

 alterations and additions in reference to numerous pro- 

 cesses, and their practical details, which he trusts may be 

 of value both to the student and general reader. 



THE THEORY OF ELECTRO-DEPOSITION. 



Inctory Remarks. As the ultimate object of this 

 chapter is to enable the reader to work in an electro plate 

 manufactory in a commercially successful manner, wu shall 

 Set ante, p. 188 ; fig. 38. 



endeavour to include within its pages, as far as the limited 

 space will allow, every portion of the subject calculated 

 to assist him in obtaining that result, excluding from it 

 every other which does not contribute towards that object. 



With this view we shall explain the principles or theory 

 of electro-deposition, because every workman in an elec-; 

 tro-plate manufactory is certain to meet with difficulties, 

 which no amount of practical knowledge or experience 

 will enable him to overcome without a perfect knowledge 

 of the theoretical principles. These difficulties may be 

 new ones, such probably as he has never seen before; and 

 no doubt, in some cases, such as no one else has ever 

 seen : a knowledge of the theory will here enable him to 

 apply principles, and suggest remedies, some of which 

 are almost sure to be successful. 



We shall also include the practice of the subject; 



