370 



NEW ENGLAND F x\ R a I E R 



MAY 



18i». 



woil.l, with SDiu.lliiliS of llie feeliii? wliicii siirs 

 in llip bcijoiiis rHS|)i;cliv(ly of a iialiiitic Freocli- 

 niari or EnL'lislinian, wlit- ii their tiimiiflits rrvert to 

 the viii-'-ODvered hills anil t,'ay rcj;ions of France, 

 or the s|>reaJing oaks and venlant lawns ol nit-rry 

 En^'land ? 



It is trnly jiraiifyinR to reflect on the progrpss 

 whii'li has heen niaile within a very few years, in 

 the study anil development of the internal re- 

 Fonrees of this country. In former times, th" 

 politieal condition of Europe, and the eniharrass- 

 liients in vvhieli we were involved hy the eonmiet 

 of the leading belligerents, formed lint only the 

 ])re(loininant, but the sole tojiics.of deep i uhlic. 

 interest. Little time <M' thought roulil be spared, 

 little at any rate was spared, for the e.vamination 

 and improvement of our internal condilion. What, 

 for instance, had been done for the advancement 

 of onr agriculture and manufactures ; and what 

 was kiio.vii of our gidd regions, our coal mines, 

 or our (juarries ? Such wa.s the state of things 

 from the very foundation of our national govtrii- 

 ineut to the si.'ning of the treaty of Ghent. It is 

 one of the chief national blessings which have re- 

 sulted from our present peaceful condilion, that 

 we have lieen enabled and induced to turn our 

 thouglits (')!!« ir(/; that the vast natural riches of 

 our land are no longer trodden under foot with- 

 out tiie slij;hlest investigation, nor ila miijestic 

 nnd beautiful scenery passed by with a lieedless 

 glance. 



Whether we regard this spirit of investigation 

 merely as political economists, or as moralists and 

 pUriots, whethtT we look to its effects on the 

 wealth or on theliajipiness of ofir community, we 

 are siire That to cultivate and to cherish it ■ must 

 be regard'eil as a sacreil duty. 



(From tlie AnitriG^n Jiiurnnl of Science and Arts") 

 TIIE NBVV ELECTRO-MAGXETIC MACHINE 



OF Mii THOMAS BiVK.\PORT OF BRAMJON, 



BUXLA.>D COUNiy, VT. 



BV PnOFESSOB SILLIMAN. 



Many years have passed since motion was f.rsi 

 produced by galvanic power. The dry columns 

 of De Luc and Zamboni caused the viiirations of 

 delicate pendulums and the rinjiing of small bells, 

 fur Ions periods of time, even several years wilh- 

 out intermission. 



In 1819-20, Prof. Oersted, of Copenhagen, dis- 

 covered that magnetism was evolved lietween the 

 poles of a galvanic battery. Pruf. Sweigger. of 

 Haile, Germany, by his galvanic multiplier, suc- 

 ceeiU'd in rendering the power manifest, when the 

 galvanic battery was nothing more tiian two small 

 wires, one of copper and the other of ziiu-, im- 

 iiiersed in us much acidulated water as was con- 

 tained in u wine glass. TJie power lliiis evolved 

 was made to pass through many convidulions of 

 insulated wire, and was thus augmented so as to 

 deflect the matrnetic neeille comeliiiies even 90 

 degret'S. Prof. Moll, ol lltretcht, by^vlnding in- 

 sulateil win; around soft iron, imparted to it pro- 

 digious nia;;nelic power, so that a horseshoe bar, 

 thus provii'ed, and eonnected with a galvanic bat- 

 tery, would lift over one huinlred pounds. About 

 till! same time, Mr Joseph Henry, ot Albany, now 

 Prof Henry of Princeton (College, by a new meth- 

 od of winding the wlie, oblained iin almost incred- 

 ible magnetic force, liliiiig six or seven hundred 

 pounds, vvi.li a pint or two oflirguid and a battery 

 of corresponding size, nor did he desist, until, a 



short time ai'ler, he lifted thousands of poi-.nds, 

 by a battery of larger size, but still very small.— 



(isso.) 



The geiitleme.n was not slow to apply his skill 

 to the generation of motion, and a successful at- 

 tempt of his is recorded in this Journal, vol. xx. 

 p. 840. A power was thus applied to the move- 

 ment of a machine, by a beam siisiiended in the 

 centre, which performed regular vibrations in the 

 uiaiiiier of a beam of a steam engine, 'ibis is 

 the ori^'inal aiiplicaiion from which have sprung, 

 or at least to which have succeeded, several sim- 

 ilar altemfits, both in this country and in Eiiro])e. 

 \ galvanic machine was reported to the IJritish 

 Association in 1835, by ;,;r McGauly of Ireland, 

 and he has renewed his statements of successlul 

 experiments at the late meeting at Bristol. Mr 

 Sturgeon of Woolwich, England, also reports a 

 galvanic machine as being in use on his premi- 

 ses, for pumi'ing water, and other mechanical pur- 

 poses.* 



But I believe that iMr Davenport, named at the 

 head of this notice, has bein more successful than 

 any other person in the discoveryt of a galvanic 

 machine of great simiiliciiy and ellieieney. Dur- 

 iuit the last two or three years, much has heen 

 said of this discovery in the newspapers, and it is 

 probable that in a future number of this Journal, 

 drawings and an accurate description of the ma- 

 chine may be given. Having been recently invited 

 to examine a working model, in two varieties ol 

 form, and to i-eport the result, 1 shall now attempt 

 nothing more than a general description, sucti as 

 may render intelligible the account 1 am to give. 

 1. The Rotary Machine, composed of revolv- 

 ing electro-magnets, with fixed permanent mag- 

 nets. 



This machine was brought to New Haven, 

 March 16, l<f!37, by Mr Israel iilade of Troy, N. 

 Y., and by him set in motion for my examination. 

 I he moving part is composed of two iron bars 

 .placed horizontally, and crossing each other at 

 ri^ht angles. They are both five and a half in- 

 ches long, and they are terminated at each end 

 by a segHvnt of a circle made of soft iron ; these 

 segments are each three inches long in the chord 

 line, and their | osition, as they are sus|iciided up- 

 on the ends of the iron bars, is horizontal. 



This iron cross is sustained by a vertical ax-s. 

 standing with its pivot in a socket, and admitting 

 of easy rotation. The iron cross bars are wound 

 witli copper wire, covered by cotton, and they 

 are made to form, at pleasure, a proper connex- 

 ion vvilh a small circular liattery, made of con- 

 centric cylinders of copper and zinc, which can 

 be immersed in a quart of acidulated water. Two 

 semicircles of strongly magnetized steel form an 

 entire circle, interrupted only at the two opposite 

 joles; and vvitirn this circle, which lies horizon- 

 tally, ihe galvanii.ed iron cross moves in such a 

 manner tiiat its iron segments revolve parallel and 

 very near to the magnetic circle, and in the same 

 plane. Its axis at its upper end is fitted by a hor- 

 izontal cog-wheel to another and larger vertical 

 wheel, t.i whose hmizontal axis, wtight is attach- 

 ed and raised by the wiinling ot a rope. As soiui 

 as the small battery, destined to generate the pow- 



• Sturgeon's Annals of Electricity, Magnetism, 

 &c. No. 1. Vol. 1. Oct. 1836. 



fMr Davenport appears to have been strictly 

 the inventor of' a method of applying galvanism 

 to produce rotary motion. 



er, is pro;;crIy eonmct" d with the machine, and 

 diilv excited by diluted acid, the motion begins, 

 by the horizonuil movement of the iron cios.s, 

 with its I'ircnlar segments or Hanges. By the gal- 

 vanic connexion, these crosses and their connec- 

 ted segments are magnetized, acquiring north and 

 south 1 olarity at their opposite ends ; and being 

 thus sub.iected to the attracting and repelling force 

 of the circular fixed magneis, a rapid horizontal 

 movement is produced, at ihe rate of two hun- 

 dred to three hundred revo'utions in a minute, 

 when the small battery was used, and over six 

 hundred vvilh a calorimetor of large size. The 

 rope was wound up with a weight of fourteen lbs. 

 attached, and twentyeiglit pouinis were lifted from 

 the floor. The movement is instantly stop|:ed by 

 breaking the connexion with the battery, and then 

 reversed by simply interchanging the connexion 

 of the wires of the battery with those f f the ma- 

 chine, when it becomes equally rapid in the op- 

 posite directian. 



The machine, as a philosophical instrument, 

 operates with beautiful and surprising eflect, and 

 no reason can be discovered vviiy the motion may 

 not bo indefinitely continued. It is easy to cause 

 a very gradual flow of the impaired or exhausted 

 acid liipior from, and of fresh acidulated water 

 into, the receptacle of the battery ; ami whei ever 

 the metal of the latter is too much corroded to be 

 any longer efticient, another battery may be in- 

 stantly substituted, and that even before ihe con- 

 nexion of the old battery is broken. As to the 

 ener''V of the power, it becomes at once a most 

 interesting inquiry, whtther it adinils of indefinite 

 increase? To ibis inquiry it maybe replied, that 

 provided the magnetism of both the revolving 

 cross and of tlie fixed circle can he indefinitely 

 increased, then no reason appears why the ener- 

 !iy of the ])ower cannot also be indefinitely in- 

 creased. Now, as magnets of the cominoi-. kind, 

 usually called permanent iiia};nets, find their lim- 

 its within, at most,the power of lilting a few hun- 

 dred pounds, it is obvious that the revolving gal- 

 vanic magnet must, in its efnciency, be litnited, 

 by ils relalion to the fixed magnet. But it is au 

 important fiict, discovered by experience, that the 

 latter is soon impaired in its power by the influ- 

 ence of the revolving galvanic iiiagnet, which is 

 easily made to surpass it in energy, and thus, as 

 it were to overpower it. It is obvious, therefore, 

 that the fixed magnet, as well as the revolving, 

 ought to be magnetized by galvanism, and then 

 there is every reason to believe that ibe relative 

 eqiia ity of the two, and of course their relative 

 energy, may be permiinently supported, ami even 

 carried to an extent much greater than has been 

 hitherto attained. 



2. Rotary IMachine, composed entirely of elec- 

 tro-magnets, both in its fixed and revolving mem- 

 bers. 



A machine of this construction has been this 

 day, INlareli 29, 1837, exhibited to me by Mr 

 'riiiimas Davenport himself, nbu came from New 

 York to New liaveu l(>r that | urpose. 



Jt is the same machine tliat has been already 

 described, except that thi! exterior fixed circle is 

 now composed entirely of elertro-niagnets. 



'ihe entire apparatus is therefore constructed 

 of soft unmagnetic iron, which being properly 

 wound with insulated copper wire, is magnetized 

 in an instant, by the jiower of a very small but- 

 tery. 



The machine is indeed the identical one used 



