Scientific.

New Zealand Mail, Issue 361, 11 January 1879, Page 7

Scientific.

SCIENTIFIC GOSSIP. (From the Leader.) The progress of invention is rapid noiv-a-days. Only a week or two ago I commented on the chief drawback of the electric light— • the want of diffusion of its illuminating power —and now the news comes that Mr. Edison has succeeded in dividing the light so that it may be had, if required, of a single rushlight power, and at an expense which is not worth mentioning. He promises not only to light up oxxr bedrooms for a mere fraction of the cost of gas, but to supply us with heat to boil the kettle and the power to work the sewing machine on equally moderate terms. The receipt of the news in London acted upon the holders of gas shares like the cx-y of “ mad dog ” in the streets, or of “ fire” in a theatre. They made a rush to dispose of their shares, and trod on each othex-’s toes in an excruciating way. Now, although Mr. Edison has made two or three decided liits out of a long array of inventions, he has few claims to reliability, and there are some points in his annoxxncement that throw discredit on the whole. He says that he has adapted Wallace’s electrodynamic machines, and these, we know, reproduce at the utmost 80 per cent, of the power of the steam engine by which they are driven. Thei-e is immense loss in the fci-ansmission. of the power thus reproduced, and as heat and power are correlatives it is an impossibility that the heat and power transmitted can ever equal the heat and work done by coal consumed in the ordinary way. He may be successful in his division of the light, for within certain limits it is done already in Europe, but the loss in ti-ansmission applies to that also, and has been found to amount to 40 per cent, in two hixndred yards. He does not say that he has obviated this loss, and so far as is known itcan only be done by the employment of enormously large and expensive conductors. A powerful current of electricity can no more be passed without loss along a small wire of great length than Niagara be made to run through a waterpipe. No good can come of shutting the eyes to sxxch a difficulty. The estimates of the expense of the light as compared with gas are very various, the most reliable l'anging from 50 per cent, below to 50 per cent, above, and the less reliable—among which Mr. Edison’s must be included—ranging from one-half the cost of gas down to nothing at all. We.may be sure that M. Jablochkoff, one of the witnesses, does not state the case unfaix’ly against his own mode of lighting, and it may be well to hear what he says. The theoretical expense of his light, in candles alone, is one-eighth of the pi’ice of gas in Paris, where it is dear, but he modestly adds:—“Although no one can prove my figures inaccurate, I should never dare to repx'esent them as reliable in practice.” There is another part of his evidence which, howevei’, is more to the purpose. He says : “ Wherever the electric light has been employed there has been a very notable economy. In the Louvre, for example, where the light has been in use for a year, the proprietors of magazines have pi*oved a saving of thirty per cent., and with more light than gas.” I do not know the price of gas in Paris, but believe that it is about double the London price, and if so the saving . of thirty per cent, there is equivalent to the loss of forty per cent, in London. It should also be noted that in many instances where the electiic light has been employed the motive power required for its production has been on the pi-emises, not far from the light, so that there has been little or no loss from transmission. The London Metropolitan Board of Works has determined to try the experiment on a large scale by lighting the Thames Embankment, and a French company have offered their aid by lending the requisite apparatus. This is an eminently unsatisfactory arrangement, for even after the trial has been made, the expense will still be a matter of estimate. In one l'espect the board displayed wisdom—they turned a deaf ear to a suggestion that they should wait for a realisation of Mr. Edison’s promises. A great many guesses have been made as to tlie nature of Mr. Eddison’s invention, but they pi’acfcically resolve themselves into two. The first is that there is a separate wire from the electric source to each house, and that by merely making the connection to complete the circuit a carbon candle is lighted, but this docs not account for the reduction of the glare to a single candle power. The second, and I think the most probable, is that the light is emittod from a platinum wire or other resisting material made incandescent when the electric curi-ent is turned on. If so, Mr. Edison has been forestalled, for the plan has been tried in England, and found to involve a great waste of electricity. He may have l-e-invented this process in ignorance of what has been already done, and it is open to hope that he has found some means of obviating the waste. Of course his plan may be altogether different from either of these, and we shall not have long to wait for elucidation, for he Is one of those men who cannot keep their own counsel ; and smart though he be, he falls into the mistake of supposing that there are no other clever men in the world. By the way, it is worthy of notice that a football match was played at Sheffield, while the ground was illumined by the electric light, but it was not a success,,for it is related that “ the brilliancy of the light dazzled the eyes of the players, and sometimes caused strange blunders.” I suspect that the mistakes were caused by the depth of the shadows as much as by the brilliancy of the light, and probably also there was some mismanagement in the arrangements.