The Daily News. FRIDAY, MAY 12, 1905. EVOLUTION OF ARTIFICIAL LIGHT.

Taranaki Daily News, Volume XLVII, Issue 7820, 12 May 1905, Page 2

The Daily News. FRIDAY, MAY 12, 1905. EVOLUTION OF ARTIFICIAL LIGHT.

If we are to judge the world's progress by the measure of the advance made in scientilic illumination tha test would hardly be fair or reliable. From the primitive ages when man rose at dawn und retired to his couch of moss or leaves when darkness covered the earth, right up to the present period when night is by muny, either from choice or necessity,, turned into day, there has been a constant demand for more light. In this, as in other matters terrestrial, the law of supply and demand haa been, and still is, carried out. There is just as much difference between the wax vesta of to-day and the ancient tedious process of creating fire by rubbing two ]>ieces of wood together, as there exists between the rushlight and the incandescent film or arc light. Although long ages have elapsetl since man first produced artificial light there have been all the while two marvellous living but silent species which tavc been pointing out to human beings the true principles on which alone success was possible. We have only to study those wonderful products of nature—the feeble glowworm and firefly, who kindle their love lamps without generating heat enough to curdle tho white of an egg —and we have at once a solution; of the problem of obtaining the best artificial light by means of a. "glow" produced in such a way that, like the light emitted from the firefly all the energy is utilised and all waste, as well as useless heat, avoided. The scientific mind lis only just realising the enormous value of the object lesson afforded by these living lights, and etlorts are being made to attack tho crying waste which is inherent to the present methods of producing high power illumination. Few people have the faintest conception of the enormous loss of energy and material that arises in connection with ,I,loth the manufacture and use of artificial lighting media. In the old days when rush lights were ill vogue the waste was far more apparent than now. The familiar and homely "dip" in vogue in our earlier days was very little better so far as economy of substance tvas concerned. A slight improvement was manifested when the "cemposite" and "wax" candles came to be improved upon, but as the light grew in power so did the heat arising therefrom, but not in such a marked degree as in the days of the oil lamp which supervened. For some time the lamp, fed by same combustible liquid, was tho only light which competed witli the candle, but tho advent of coal gas has almost entirely sujierseded both; the lamp amd tho candle, which still hold their own in other districts, and oven in towns where the gas supplied is of inferior quality or iji exorbitant price. Lastly, science has given us tho electric I l'ight, which as yet may be deemed to be only in its experimental stages, for there is not the slightest doubt but that many improvements will be effected. Even now there !s another light-giving medium discuss.m!—the wondrous radioactivity of which so little is yet known, but from that little great possibilities are expected. One prominent fact seems to stand out in this question of lighting—tho successlul illuminant must be a "glow." Combustion is to be a thing of the past), and incandescence tili 1 light of the future. It hardly seems possible that so long ago as 1826 IH'ummonil demonstrated tfie marvellous power of the glow li'giht by causing an ignited jet of mixed oxygen and hydrogen to impunge upon a cylinder of lime, producing a light so vivid and controllable that it exists to this day, though naturally it is quite unfit for domestic purppses. The main factor in tlu; question of the manufacture and distribution of artificial light;, apart from that of quality, is the price at whidi it can be supplied. It stands to reason that if an article, of commerce is manufactured in such a way that little, if any, waste takes place during the process, it can bo placed on the market at a very reasonable rate, but that as the ratio of waste arises so must the ultimate cost to the purchaser be ieoj-diijatei/ .increased. X'rofes-i

1 sor Langley, of the Smithsonian In- 1 stitute at Washington, has put the glowworm and firefly to the test,, and compared their effective light with that of our lamps with marvellous results. He finds th-iit the porceu-Ugts of elective energy- -in' producing light are : —For the ttrc light for gas light 1.5, for the

solar spectrum 15, and f° r r(i ~ fly ] that is, all the energy of the latter is utiiisoJ in producing light and none wasted, while in the ca.se of ekotricity and gas the waste and useless heat amount to about , 98 per cent. Looking at this phasii of the question front a tinanc.al point of view il would appear 'that about ninety-eight shillings out 'of every hundred spent in producing the gas light is practically thrown away every day. This sooms to be incredible, |>ut yet t here is no reason for doubling the high authority sponsible for the startling theory. We have merely given this illustration to show that the success achiovtl by Nature has not yet been ac-

complished by art. hut there is no reason why it may not arrive at any moment. Great as have been the strides which' one system of artificial light has made over that which it superseded, there is still much to bo done in the wide domain of research before this important matter is satisfactorily solved. Meanwhile thero is a fruitful field for argument in discussing the relative merits of electric light, arid the incandescent

gas mantles of Auer von Wolsl>acb. So groat ly are wo dependent on artificial light that any improvement is heartily welcomed so long as it does not increase the illumination at tho expense of our vital powers by vitiating the atmosphere we breathe.

ON THE FOURTH PAGE. Literature.