VOt,. XV. NO. 47. 



AND GARDENER'S JOURNAL 



87 1 



before, except tliat the exterior circle of |iiMin:i- 

 neiit iiia';nets is removed, aud in its place is ar- 

 ranged a circle of soft iron, divided into two ])or- 

 tions to form the poles. 



These semicircles are made of lioop iron, one 

 inch in width, and one eiglitli of an inch in ihiik- 

 ness. They are wound with copper wire insula- 

 ted by cotton — coverinj; about ten inches in 

 lengtli on each semicircle, ami retnrninf; niion it- 

 self, by a double wiiuliiii;, so as to foi tii two lay- 

 ers of wire, nuiking on both semicircles about 

 1500 inches. 



The iron was not w-ound over the entire length 

 of one of the iron semicircles, but both ends were 

 left projei:tin^, and being turned inward, were 

 made to conform to the bend of the other part ; 

 each enil tliat is turned inward, and not wound, is 

 about one third of the length of the semicircle. — 

 These semicircles being thus fitted up, so as to 

 become at phasure, galvanic magnets, were placed 

 in the same machine that has been already des- 

 cribed, and occupied the same place that the per- 

 manent steel magnets did before. The conduc- 

 ting wires were so arranged, that the same cur- 

 rent that charged the magnets of the motive wheel, 

 charged tiie stationary ones placed aroiuid it, on- 

 ly one battery being used. ItshouM he observed, 

 that tli(! stationary galvanic niigncts thus substi- 

 tuted for the permanent steel luies, were oidy 

 about half the weight of the steel magnets. This 

 modification of the galvanic magnet is not of course 

 the best form for efficiency ; this was used mere- 

 ly to try the principle, and the construction may 

 be supers -ded by a different and more efiicient 

 one. Hut with this arrangement, and notwith- 

 standing the imperfection o( the mechanism of the 

 machine, when the battery, requiring about one 

 quart of dilutcMl acid to immerse it, was atltaclied, 

 it lifted IG pcjunds very rapidly ; and when the 

 weiirht was removed, it performed more than 600 

 revolutions per miiuite. 



So scfusihle was the machine to the magnetic 

 power, that the immersion of the battery one inch 

 into the acidulated water, was sufficient to give it 

 ra|)id motion, which attained its maximum, when 

 the battery was entirely immersed. It appeared 

 to me that the machine had more energy wi'Ii the 

 electro-magnets, than with those that were per- 

 manent, for with the smallest battery, whose di- 

 ameter was three inches and a half — its lieight 

 five inches and a half, and the nund)er of concen- 

 tric cylinders three of copper and three of zinc, 

 the instruments rnanifisted as great power as it 

 had done with the largest batteries, and even with 

 a large ealorirnetor, vvlnm it was used with a per- 

 manent instead of a galvanic magnet. With the 

 small battery and with none but electro or gal- 

 vanic magnets, it revolved with so nnieh energy 

 as to produce a brisk breeze, anil jiowerfully to 

 shake a l.'uge table .in which the apparatus stood. 



Although the magnetization of both the station- 

 ary ami revolving magnets was imparted by one 

 of the same battery, tlie magnetic power was not 

 immediately destroyed by breaking the connexion 

 between the battery and the stationary inagnet ; 

 for, when this was <]one, the tnachine still per- 

 formed its revolutions with great, although dimin- 

 ished energy ; in practice this might be impor- 

 tant, as it would give time to make changes in the 

 apparatus, without sto|iping the movement of the 

 machine. 



It has been stated by Dr llitcdiie, in a late num- 

 ber of the London and Eiliub. Phil. Magazine, 



that ('lectro magnets do mil attriicl at so great a 

 distance as permanent ones, and therefore are not 

 adapteil for producing motion. On this point, 

 Sir Davenport madi? the following experiment, of 

 which I was not a witnes.«, but to whic-li I give 

 fuTl credit, as it was reported to me by Mr Siade, 

 in a letter dated New York, March 24, 1837. 



Mr Davcnpurt suspended a piece of soft iron 

 with a long piece of twine, and lir Might one pole 

 of a highly charged steel- magnet w tiiiu the at- 

 tracting distance, that is, the distance at which 

 the iron was attracted to the magnet ; by meas- 

 urement, it was fuuiwl that the steel inasnet at- 

 tracted the iron one inch and one fourth. A gal- 

 vanic magnet was next used of the same lifting 

 power, and consequently of much less weighty 

 the attracting dista;i('e of this magnet was found 

 to be one inch and three lourths, shewing a ma- 

 terial gain in favor of the galvanic magnet. 51r 

 Slade inquiies, "has Mr Ritchie's magnet been so 

 constructed as to give a favorable trial on the 

 principle ?" * Mr Davenpi>rt informs me thai 

 e;icli increase in the number of wires has been at- 

 tended with ail increase ol power. 

 Conclusions. 



1. It appears then, from the facts stated above, 

 that electro-m.-ignetism is quite adequate to the 

 generation of rotary motion. 



2. That it is not necessary to employ perma- 

 nent magnets in any [lart of the construction, and 

 that electro-magnets are far preferable, not only 

 for the moving, but for the stationary parts of the 

 machine. 



3. That the power generated Iiy electro-mag- 

 netism may be indefinitely prolonged, since, for 

 exhausted acids, and corroded metals, fresh acids, 

 and batteries, kejjt always in readiness, may be 

 substituted, even witi:out stopping the move- 

 ment. 



4. That the power may be increased beyond 

 any limit hitherto attained, and probably beyond 

 any which can be ivilh ccrlainiij assigned, — since, 

 by increasing all tFie niembeis of the apparatus, 

 due reference being had to the relative propor- 

 tionate weight, size and form of the fixed and 

 moveable jiarls, — to the length of tFie insulated 

 wires anil the iranner of vvi!:diiig them — and to 

 the proper size and constriicti )n of the battery, 

 as well as the nature and strength of the acid or 

 other exciting ag(;nts, and the manner of connect- 

 ing the t)tttery with the machine, it would aj'pear 

 certain, that the power must be increased in some 

 ratio which experience must ascertain. 



As electro-magnetism has been experinentally 

 proved to be snfKcicnt to raise and sustain several 

 thousand of pounds, no reason can be discovered 

 why, when the acting surfaces are, by skilful me- 

 chanism, brought as nearas possible, without con- 

 tact, the continued exertion of the power should 

 not generate a continued rotary movement, of a 

 degree of energy inferior indeed to that exerted 

 in actual contact, but si'll nearly approximating 

 to it. 



6. As the po\^er can be generated cheaply and 

 certainly — as it can be continued indefinitely — 

 as it has been very greatly increased by very sim- 

 ple means — as we have no knowledge of its lim- 

 it, and may therefore presume on an indefinite 

 augmentation of its ener^'y, it is much to he de- 



*This question I am u lable to answer, as I 

 have not seen any account of the apparatus or of 

 the experiment, but only of the result. 



sired, that the investigation should be | roseculed 

 wiih zeal, aided by correct scientific knowledge, 

 by ni ■chanical skill, and by ample funds. It may 

 therefore be reasonably hojifd, that science and 

 art, the handmaids of discovery, will both receive 

 from this interesting research, a liberal reward. 



Science has thus, must iinexpe<'tedly, |hiced in 

 our hands, a new jiower of great, but unknown 

 energy. 



It does not evoke the winds from their caverns ; 

 nor give wings to water hy the urgency of In at ; 

 nordrive to exhaustion the muscular power of an- 

 imals ; nor operate by complicated mechanism ; 

 nor accumulate hydraulic fm-ce, by damming the 

 vexed torretits ; not summon any < tlier form of 

 gravilating force ; but, by the simplest means — 

 the mere contact of metallic surfaces of small ex- 

 tent, w ith feeble chemical agents, a power every 

 where diffused through nature, hut generally con- 

 cealed from our senses, is mysteriously evolved, 

 and by cii dilation in insulated wires, it is still 

 more inystei ioiisly augmented, a thousand and a 

 thousand fold, until it breaks forth wiih incredi- 

 hie energy ; there is no appreciable interval be- 

 tween its first evolution and its full maturity, and 

 the infant starts up a giant. 



Nothing since the discovery of gravitation and 

 of tl>e strut ture of the celestial systems, is so won- 

 derliil as the powerevolved bycaivanism; wheth- 

 er we contcm[>'ale it in the muscu'ar convn'sitms 

 of animals, the clii'iiiical decompositiouf!, the solar 

 brightiies.s of the galvanic light, the <lissipating, 

 consuming lieat, and nitre than all, in the mag- 

 netic energy, which leaves far behtiid a!! nrlifu-ial 

 accutnuhitions of this power, and reveahs, as there 

 is full reason to believe, the grand secret of ter- 

 restrial magnetism itself. B. S. 



New Haven, March 31, 1837. 



Claim of Thomas Davenport 



In the word of the patent, taken out, tbis in- 

 vention "consists in applying magnetic and elec- 

 tro-magnetic power as a moving principle for ma- 

 chinery, in the manner described, or in any other 

 substantially the same in principle. " 



" Mr Davenport first .saw a galvanic tnagnet in 

 December, 1833, and from the wonderl'ul effects 

 produceil by suspending a weight of 150 lbs. from 

 a small galvanic magnet, he immediately inferred, 

 without any knowledge of the theory or the ex- 

 periments of others, tnat he could piofiel machi- 

 nery by galvanic magnetism. He purchased the 

 magnet r,nd produced liis first roi.iry motion in 

 Jiilvy 1834. In July, 183.5, he submitted his ma- 

 chine to Prof. Henry, of Princeton, N. J-. also with^ 

 out any knowleilge of Prof. Henry's experiments 

 in producing a vibratory motion. From this gen- 

 tleman, he received a certificate, testifying the 

 nri?iuality ;|:id itnportfluce of the invention." 



Mr Davenport is, by oc^-u[iation, a bhu ksmith, 

 with only a common education, but with uncoui- 

 mon intelligence; ids age about thirtyfive. Mr 

 Kansnm Cook, of Saratoga Springs, is associated 

 with Mr Davenport, and ha.s rendered essential 

 service by the iiutirovemenls he has made in tho 

 machine, and by his assistaKce in bringing tho 

 subject before the luiblic in the most elTcptual 

 way. Arrangemeiils have been made to takeout 

 the patent in Europe. 



P. S. The propri >tors are constructing a ma- 

 chine of 7 inches in diameter, and also one of 2 

 feet in diameter. G;dvai:ic magnets will he lised 

 as the moving and statii nary tiiagnets of each. 



