At i recent meeting ot' the British Association, Prof. W. E. Ayrton : livered a lecture on the above subject, and interestingillustrationsweregiven including machinery, in motion, driven ■ by power derived from a distance. The lecturer said: Various calculations had been made as to the relative cost of lighting by burningcoal to produce gas, or by burning coai to work dynamo machines for produclng electric cúrrente, and it seemed to be pretty certain that ií a large amountof ligbt be required in one place, the electric light was at least tvvonty times as cheap as coal. sir William Thompson, the eminent electrician, went so far as to say that it might be made 133 times as cheap. And certainly that there was a great saving in expense in electric lighting was seen from the actu,iti m L.ii ; .i i wi m .-- Au...,., i ., i : Lon3on, wliicli v:is an example, and perhaps the only example, in tion witb electnc ugntvng, wnere t.ne seience of putting a brilliant light high up had been allowed to ride over the precedent of putting a number of feej]e glimmers all over a building. The actual cost, inciuding labor of men, allowance for wear and tear of machinery, etc, was only one-third of that of ;he f ormer inferior gas lights, and thus asaving of about 80a, an hour had been iffected. Lighting streets by electricity had not been so successiul econoniically, for the simple reason that InBtead of giving a large bright light, at a considerable height reflected downwards, as in the Albert Hall, Lon&on, English conservatism had prevented the authorities from grasping the possibility of using for street illumination anything different from an ordinary iron lamp post. But there could be iittle doubt that if a few large electric lights, high up, were used for street illumiiiation, the same sort of result as has been obtained at the Albert Hall would be arrived at. Assuming that the cost of gas for lighting the large buildings, factories, and the streets of Sheffield could be halved, also that where it was used for heating purposes the expense, could nlso be halved, by substituting electric cúrrente generated by very large steam engines at certain points, and by turbines driven by falling water out of the town ; then they would save per year about L45,000. Supposing, also, that the cost of producing motive power could in the same way also be halved, this represented an animal saving of something like L00,000. And, lastly, supposing the consumption of coal " in Sheffleld for heating their metáis and for heating their houses could also be halved, then there was íinother suving of about L300,000 a year ; or, altogether, the annual sayiiijr that might be produced in this tovvn alone, by substituting electricity for coal, would be sometliing like the large sum of L400,000. Last year, two French engini MM. Chretlen and Fnlir. ni oj.ia) (Mame), actuallyplowed íields by electricity, the electric current being produced by two dynamo-electric in' chines of a form inyented by M. Gramme. These machines were usually worked with a steam engine at some convenient place three or four hundred yards away in an adjoining road, and the electro-motors were also two Gramme machines, one on each side of the field, with their coils revolving of course backwards. Through one of these the electric current was sent alternately, so that motion wa3 líiyen to one or other of two large windlasses, one on each of the wagons containing the electro-motors. In this way the plow, which could be used göing in either direction, was íirst pulled across the field, making a furrov and then back again, making another parallel furrow.