SCIENTIFIC GOSSIP.

Lyttelton Times, Volume LIII, Issue 5918, 13 February 1880, Page 6

SCIENTIFIC GOSSIP.

(By Salvia.) *' What cannot art and industry perform When science plans." —Beattie. For a time so much, popular apprehension existed among the English people regarding the exhaustion of their coal supply that a Royal Commission was appointed to inquire into the matter. They reported, after due examination into the subject, that the total available coal within the United Kingdom, was not likely to be exhausted under from 276 to 360 years, at the rate of consumption going on in 1871. Notwithstanding this long period before the coal supply will be exhausted, a writer in Vlnginieur Universal thinks it is worth while for England to be inquiring now what substitute can be drawn upon for coal. For purposes of iron smelting there is no good substitute known except charcoal, and obviously its employment is out of the question in England. Therefore, the writer concludes that there is very little prospect at present of inventive ingenuity doing much to supersede the use of coal in this direction. But for many mechanical and useful purposes a substitute would not be difficult to find. The writer thinks it has been demonstrated that coal gas for illuminating purposes can be superseded with advantage, and it is obvious that mechanical genius may any day work similar marvels in other departments where coal has hitherto been considered a necessity. There is no present prospect of such a result occurring in iron smelting; but for mechanical purposes increased attention is now being directed to hydraulic power—a power which has been too much neglected in our times of abundant coal supplies. He then repeats Dr Siemen’s calculations of the power that is daily running to waste at the falls of Niagara, where 100 million tons of water fall some 300 feet every hour. The force represented by the principal fall alone amounts to 16,800,000 horse power; and to produce the same amount of power by steam would require 266 • million tons of coal per annum —an amount which all the coal raised in the world would scarcely be sufficient to supply- Tremendous as this appears, the calculation may bo regarded as more curious than useful ; for as the district around Niagara is destitute of minerals, the water power of the Falls is never likely to bo utilised. But the calculation may be usefully applied to other places. Sir William Armstrong has done good service in the way of showing how to carry and utilize water power at a _ distance by conveying it through high pressure mains. For instance, were this power generally employed, where possible, to give motion to dynamo-electrical machines, the electric light could not only be produced altogether without the use of coal, but it could be carried to a great distance, illuminating towns distant from coal fields at less cost and in a superior manner to anything

that has ever been done by gas. Another means that is capable of more extensive application is compressed air, which has been employed with wonderful results in some places on the Continent. Still, when all these and other sources of power are brought into more extensive requisition, coal will continue to be indispensable for many purposes. But though the stock in store is immense, the coal trade in the future is likely to experience greater vicissitudes than in the past; and with the recollection of the fluctuations of the last ten years still fresh in the public memory, it is well as far as it is possible to provide a second string to our bow, so that when one source of power fails another may be readily available. Bays Professor Wilson, in Science for All: A rotting apple is allowed to remain neglected in some corner of a closet, and there springs up from its decaying surface a crop of one or more forms of mould. Two such apples, obtained from the same tree, and otherwise identical in every respect, shall be similarly exposed in two different closet*; the one may become covered with one species of mould, and the other with a different one. Buch differences as these have been observed to result in the case of experiments conducted within a few inches of each other, and can only be explained on the supposition that the germs of various species of mould were floating in the air, and that some of one species fell upon one apple, while those of a different species reached the other. These germs, or spores, are so exceedingly minute and light, even when freshly gathered from their parent plant, that they float before the breeze with the greatest readiness; but when dried up—a process which they are capable of enduring without any loss of their vitality—they become almost imponderable: hence feeble atmospheric currents are capable of carrying them into tho most remote and sheltered corners. That they mingle freely with the visible dust is shown by the observations to which I have alluded it is difficult, perhaps impossible, to identify tho spores of these moulds and other fungoid plants with absolute certainty, since objects that are not distinguishable from them are also readily caught in the glycerine traps to which ! have referred. Mr Cecil J. Saunders, in a paper read at a late session of the Musical Association, in England, on the Construction of Buildings ! considered in Reference to Sound, made some very interesting statements and advanced I some curious theories. Glass being one of the most elastic of sound reflectors, he was 1 not surprised to find, when listening to a concert at tho Crystal Palace, that the echo of one note returned to him at the same instant that he received the next note direct. He said that light had a remarkable modifying influence on sound, a statement which was ! corroborated by gentlemen who took part in | the discussion that followed the reading of the Eaper, although the general opinion seemed to e that the cause lay not in the light itself but in the heat produc d by it. Mr Saunders then described the ball that he would have i built to contain five thousand auditors. Tt would be a square room with rounded corners, and the orchestra in one of the corners. The audience would face the orchestra, and would thus look toward the converging walls. The number of performers provided for would be 700, as this was probably the limit of really i good work, the orchestra seats rising tier above tier into the angle of the building. The organ should be chiefly below the orchestra, so as to ; allow of a low ceiling. By placing the i orchestra in the angle of the building, very few I of the audience can receive an echoed sound, j The seats for the audience should be circular, ! so as to give every one a direct view. The 1 floor should rise gradually toward the back of I the room. The best material for the ceiling ■is wood. Ordinary plastering is one of the most perfect non-conductors of sound used in building. Zinc would be nearly as cheap, and perhaps even more efficacious than wood. The walls at the back of the orchestra should be covered with looking glass, which has a strong reflecting power for sound. These glasses, however, should not be bedded in flannel as usual, but allowed to vibrate with every note. Boarding or cement would be best for the rest of the walls. Cement is hardly resonant, but it reflects sound well. Stone would do better, but fits cost is too great. Ho doubt a good deal of the resonance of cathedrals is due to the surface of smooth and hard stone inside them. For quartet performances, a movable screen behind the players or singers might be arranged so as to re-enforce the sound in its forward direction. This screen should oe of two thicknesses of wood, with a sounding-board at the top inclined slightly upward. Empty and halfempty rooms always echo, so that the best way of avoiding an echo is by low prices and a good programme. When there is a certainty of a small audience in a large hall, heavy curtains should be hung from the ceiling, so as to reduce its size. From experiments by Mr J. T. Bottomley, a report on which was read before the British Association at Sheffield, it seems that the prolonged application of stress has a very remarkable effect in increasing the strength of soft iron wire. Comparing the breaking weights for a wire quickly broken with those for the same wire slowly broken, it is found that in the latter case the strength of the wire is from 2 to 10 per cent higher than in the former, and is on the average about 5 or 6 per cent higher. The result as to elongation is even more remarkable, and was certainly more unexpected. In the case of the wire quickly drawn out, the elongation is, on the average, mure than three times as great as in the case of the wire drawn out slowly. There are two wires for which the breaking weights and elongations are given in tho tables accompanying tho report, both of them “bright” wires, which showed this difference very remarkably. They broke without showing any special peculiarity as to breaking weight, and without known difference as to treatment, except in the time during which the application of the breaking weight was made. One of them broke with 441 b, the expe> iment lasting one hour and a half; the other with 471 b, the time occupied in applying the weight being 39 days. The former was drawn out by 28 5 per cent on its original leng» h, the latter by only 4 - 79 per cent. It was found during the breaking of the. wires slowly—several months—that the wire becomes alternately more yielding and less yielding to stress applied. Thus, from weights applied gradually between 281 b and 311 b or 321 b, there Is very little yielding and very little elongation of the wire. For equal additions of weight between 331 b and about 371 b the elongation is very great. After 371 b have been put on, tho wire seems to get j stiff again, till a weight of about 401 b has ■ been applied. Then there is rapid running down till 451 b has been reached. The wire then becomes stiff again, and often remains so till it breaks. Various instances have been recorded of the discovery in hens’ eggs of minute specimens of the distoma ovatum. They appear like a small speck, the size of a millet seed or a pin’s head. It is believed by helminthologists that these will develop into one of the varieties of tape worm, and it is Wise, therefore, to take eggs hard boiled or otherwise well cooked. A writer in one of tho late numbers of Nature cites several instances where these parasitic bodies have been found.