1844.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL 



231 



The application of electro-magnetic power to a practical purpose has occu- 

 pied the attention of many able and ingenious men, and it has been carried to 

 such an extent that its ultimate success may be foreseen, although, at the 

 present moment, economical difficulties stand in the way. The number of 

 these inventions is very great, so that we may anticipate, from the amount of 

 time and talent devoted to the subject, a practical solution of the problem is 

 not far distant. To give anything like a connected history of this subject 

 would take up far more time than it is in our power to afford, neither is it 

 necessary to do more than allude to some of the more prominent plans, which 

 exhibit the principles on which the inventors have proceeded. In 1837, Mr. 

 Davenport, of Vermont, U. S., took out a patent for a rotary engine, thus 

 c nstructed : the moving part is composed of two Iron bars, placed horizon- 

 ally, and crossing each otherat right angles, these are covered with insulated 

 copper \vire, and sustained by a vertical axis, and having proper connection 

 with the voltaic battery in the usual mode. Two semicircles of strongly mag- 

 netized steel form an entire circle, interrupted at the two opposite poles only, 

 and within this circle, which is placed horizontally, the galvanized iron cross 

 moves in such a manner that its iron segments revolve parallel, and very near, 

 to the magnetic circle and in the same plane. The axis of the cross at its 

 upper end is fitted by a horizontal cogwheel to another larger vertical wheel 

 to the horizontal axis of which the weight is attached, and raised by the 

 winding of a rope. By the galvanic connection these crosses and their con- 

 nected segments are magnetized, acquiring north and south polarity at their 

 opposite ends ; and being thus suljjected to the attracting and repelling force 

 of the circular fixed-magnet a rapid horizontal movement Is produced, at the 

 rate of six hundred revolutions in a minute, when a large calorimotor is em- 

 ployed. The movement is stopped in an instant by breaking the contact with 

 the battery, and then reversed by simply Interchanging the connexion of the 

 w ires of the battery with those of the machine, when it becomes equally rapid 

 in the opposite direction. 



We should remark for the benefit of our readers that Mr. Noad's eighth 

 lecture contains much useful information as to electro-magnetic motive 

 power, and electro-magnetic locomotion, from which lecture we select the 

 following list of some electro-magnetic machines, with the references to the 

 periodicals in which descriptions are contained. 



" Sturgeon's Electro-magnetic Engine for turning Machinery. ' Annals of 

 Electricity.' Vol. i. p. 7-5. 



"Jacobi's valuable paper on the application of Electro-magnetism to the 

 moving of machines, with a description of an Electro-magnetic Engine. 

 'Annals of Electricity.' Vol. 1. p. 408-119. 



Mr. Joule's Electro-magnetic Engine. 'Annals of Electricity.' Vol. il. p. 

 122. 



"Mr. Davenport's Electro-magnetic Engine. ' Annals of Electricity.' 

 Vol. ii. p. 257. 



"The Rev. F. Lockey's Electro-magnetic Engine. ' Annals of Electricity. 

 Vol. iii. p. 14. 



"Dr. Page on Electro-magnetism as amoving power. 'Annals of Electri- 

 city.' Vol. iii. p. 554. 



" Mr. Joule's second Engine. ' Annals of Electricity.' Vol. iv. p. 203. 

 " Mr. Uriah Clarke's Engine. ' Annals of Electricity.' Vol. v. p. 33. 

 " Mr. Thomas Wright's Engine. 'Annals of Electricity.' Vol. v. p. 108. 

 " Mr. U. Clarke's Electro-magnetic Locomotive Carriage. ' Annals of 

 Electricity.' Vol. v. p. 304. 



•' Jacobi on the 'Principles of Electro-magnetical Machines.' Report of 

 the Meeting of the British Association in Glasgow in September, 1S40. ' An- 

 nals of Electricity.' Vol. vi. p. 152. (This is a most valuable paper, and is 

 well deserving of attentive study.) 



" Mr. Robert Davidson's Electro-magnetic Locomotive. ■ Engineers' Ma- 

 gazine,' &c. Part 15, p. 48. 



" Mr. Taylor's Engine. ' Mechanics' Magazine.' Vol. xxxii. p. 694. 

 " Mr. Watkln's Electro-motive Machine. ' Phil. Mag.' Vol. .\ii. p. 190. 

 "An Inquiry into the possibility and advantage of the application of Elec- 

 tro-magnetism as a moving power, by the Rev. James William M'Gauley. 

 " Report of the Proceedings of the British Association for the Advancement 

 of Science at the Dublin Meeting, August, 1835.'' 



In 1838, as it will be remembered, Capt. Taylor's eleclro-magnetic engine 

 was exhibited. It is thus described: — "Mr. Taylor employs as his prime 

 movers, a series of electro-magnets, which are alternately and almost Instan- 

 taneously magnetized and de-magnetized, without any change of polarity 

 whatever taking pl.ice, and In bringing certain other masses of iron or electro- 

 magnets successively under the influence of the said prime movers w hen In a 

 magnetized state, and in de-magnetizing the said prime movers as soon, (or 

 nearly so.) and as often as their attractive power ceases to opei'ale with ad- 

 vantage; or in other, and perhaps plainer words, his Invention consists in 

 letting on or cutting off a stream of the electric fluid in such alternate, quick, 

 and regular succession, to and from a series of electro-magnets, that they act 

 always attractively or positively only, or with such a preponderance of 

 positive attraction, as to exercise au uniform moving force upon any num- 



ber of masses of Iron or magnets placed so as to be conveniently acted 

 upon. Mr. Henley constructed a very large electro-magnetic engine, on Cap- 

 tain Taylor's plan, at the time that that gentleman took out his patent. The 

 wheel was 7 feet in diameter, and weighed 4 cwt. This machine did some 

 work, but at an enormous expense, 6 cwt. of suljihate of copper having been 

 consumed in one week, in experiments alone. The battery employed con- 

 tained 13 cwt. of metal." 



In 1837, Mr. Davidson had also applied himself to the subject. His machine 

 dlders little in construction or principle from that of Capt. Taylor. In 1842, 

 Mr. Davidson constructed a large electro-magnetic locomotive, and tried it 

 on the Edinburgh and Glasgow Railway. " The carriage Is sixteen feet long 

 and six feet broad and weighs above five tons, including batteries, magnets, 

 &e. The electro-magnets are not one solid piece of iron, nor are they rounded 

 behind. Each of the side parts or arms Is constructed of four plates of soft 

 iron put together, so to form as it were a box for the sake of lightness. The 

 arms are twenty-five inches long and joined together behind by plates of 

 iron. Their rectangular poles measure eight by five inches, and at their 

 nearest points are only about four inches asunder. The colls with which they 

 are surrounded do not consist of a single copper wire, but of bundles of wire 

 wrapped round with cloth to insure insulat'on. According to Mr. Davidson's 

 first arrangement these magnets were placed so that their poles were nearly 

 in contact with the revolving masses of iron in their transit: but su prodi- 

 gious was the mutual attraction, that the means taken to retain the magnets 

 and Iron in their assigned position were Insufficient." 



This machine only realized four miles an hour, being less than that of a 

 single man, who could on a level railway move a carriage of the same weight 

 with equal velocity. 



Professor Jacob!, of St. Pelersburgh, tried In 1838, at the expense of the 

 Russian government, the experiment of propelling a boat by electro-magnet- 

 ism. The vessel went at the rate of four miles an hour with the stream 

 and three miles against it, which as Mr, Noad remarks, is more than was 

 realized at first with tlie steam-boat. 



The accompanying engraving represents a small working model of an 

 electro-magnelo-motive engine, constructed by Mr. Bain and improved by 

 Messrs, Knight and Son. 



Fig. 8. 



",0n to a stoutimahogany board'are fixed the brass uprights £ £; to these are 

 attached the electro-magnets A B, covered with stout wire \ through the 

 upper part of these uprights, and above the magnets, the two endsof the steel 

 spindle c work ; this spindle carries about its centre an Iron bit, which is 

 alternately attracted by the t«o magnets .1 and B, but prevented from abso- 

 lute contact by pieces of paper ; another spindle in, at right angk s with c, and 

 supported by the uprights /i //, carrying at one end the fly mIiccI /,-, and on 

 the other a small pully. Is cranked In the centre and connected with c by the 

 spring and hook b. At li are seen two brass springs bearing lightly on the 

 spindle, which Is divided In the middle by a small piece of Ivory, so that one 

 only is in contact at the same lime. The connections are formed thus : — one 

 termination of the eleetru-magnet./ is connected to one of the upright springs 

 bearing on the spindle, and the other termination to the binding screws seen 

 at the end of the board. The one termination of theelectro-rnagnet/? is con- 

 nected with the otiier spring, and the oiher extremity to the same binding 

 screw to which one end of A was attached, the remaining binding screw being 

 in connection by means of a wire with the brass box In which m works. The 

 working of this machine Is greatly assisted by two spiral springs fixed under- 

 neath the board attached to the moving bit. The whole arrangement per- 

 forms extremely well, and no doubt if made on a large scale would be very 

 powerful. 



