SCIENCE NOTES.

New Zealand Times, Volume LXXVII, Issue 5372, 3 September 1904, Page 16

SCIENCE NOTES.

THE WORLD'S MINERALS. “Tho Sciences and Art of Mining” says that Great Britain’s coal output per person docs not work out in due proportion to persons employed. That is brought about by a variety of causes. The coal is not obtained with quite the same ease as in somo countries, whore again the Iron Man, and especially so iu Iho United States, is an important factor tending to raise the average output. \Yc have coal-rutting machinery in Britain, but the number of machines doing useful service may be easily counted, whereas in America the coal cutters are extensively used. The' result is that the States are leaving us behind in the matter of total production, though, unlike some people who are greatly perturbed thereat, we do not think it is a question about which we need to be much concerned. America is a vast continent, hut we cannot add to the acreage of these tight 111 tie isles of ours, though we arc doing tho next best thing—we are adding year by year to the gross mineral output. The world’s product in 1902 was 803,157,0-15 tons. That is a vast quantity and wo provided more than one-fourth of it. Our exact total was 230,739,359 tons, and with the assistance of the colonies it was raised to 256,903.411 tons, that is, for the Empire, Tho United States produced 273,609,0-31 tons, the German Empire 250,800,214 tons, Austria-Hun-gary 39,479.560 tons. France 29,997,470 tons, and Belgium 22,877,470 tons. The supply of coal is not unimportant to the two nations engaged in mortal combat in the Far East, mid wo notice that the annual output of Russia is 16,151,55/ tons, that of .Japan being 8,911,933 tons. These aro the only important foreign coal-producing countries, the remainder, with the exception of Spain with 2,807,550 tons, failing to reach the million mark. As to Greater Britain. India heads the list with 7,513,625 tons, Australia with 5,968,514, Canada with 6,930.220, the Transvaal with 1.G15.851, and New Zealand with 1,334,570 tons following in due order. SINGLE STEREOSCOPIC PHOTO GRAPHS. Dr Gradenwitz describes in a recent number of "Knowledge” a new method of taking stereoscopic photographs and a new lens for viewing them, by means of which the photograph assumes the apparent solidity characteristic of ordinary double stereoscopic photographs. He says:-—An eye of normal vision will perceive through the lens, not tho photograph as it appears to tne unaided eye, but* a far distant image of it, free from distortion, and under tbo same conditions of apparent size, distinctness, perspective, light and shade as those under which tho objects then?solves would be seen with the short photographic objective that has been mentioned. Consequently the small photograph conveys to tho cyo a much more natural effect than a landscape photograph can possibly do; and unconsciously the vision forms "in tho mind a correct perception of relief and distances. Thus although the stereoscopic effect is not of the same kind as that produced iu ordinary stereoscopes, tho effect of solidity is strongly evident and perceptible.

THE HEAT OF THE EAJfTH—STARTLING THEOK V. Tu llio course of a lecture before the Roval Institution. Professor K. Rutherford throw out a startling suggestion as to tlio cause of (Tie earth's heat. The lecturer remarked that Lord Kelvin, in his estimate of the world’s age, had qualified his words by adding/'providscl a new source of heat is not discovered." A new source has been discovered in radium, and Professor Rutherford suggested that adding to the three known variations of the emanations of radium there might bo a fourth which can bo gauged and measured after about 200 years of observation of on© speck of radium... It is therefore possible that further variations might bo traced through aeons of years, and as radium was thought to be contained in all matter, it is certainly not improbable that it is the source of the earth’s heat. This theory leads to the startling but by no means new conclusion that the earth may have been habitable for many millions of years. HYPNOTISM CUBES WRITER’S CRAMP. It 'is contended by M. Berillon that the term "stammering" ought to bo extended so as to include analogous difficulties in writing. Many persons are incapable of writing even one of the letters of a word so long as anyone is looking at them, but this timidity only exists when they attempt to write in public. M. Berillon cites the case of a medical man who when, ho was a student was never able to sign the attendance book, and each time had to get one of his friends to do it for him. Recently when meeting one of his former teachers in consultation he by an artifice indticed the latter to writ© the prescription as ho himself was unable to hold the pen. The timidity of these "stammering writers" is tlio result of two principal factors —namely, emotion and indecision; it is quite amenable to hypnotic suggestion, which has in a certain number analogous cases given excellent results. MEDICINE AS A MORAL AGENT. In the olden times, and even up to the present, ,tho universal panacea in the case of a sulky, stupid, or ill-tempered boy waA commonly believed to b© in the application of the rod, but it is now believed by a certain school of psychologists that with the judicious. use of internal remedies his, case is better reached. than by.; the tiihe-honoured method of counter-irritation: A clearer insight would discover the, salutary effects of a dose of castor oil in many instances. A contemporary states that a correspondent once knew the .wife of a physician who habitually administered purgative doses of calomel to her two little boys with the solo intention of improving their dispositions. No less an authority than Dr Lauder Bruntou has directed the attention of the profession to the fact that many quick-tem-pered persons are really victims of masked forms of gout or rheumatism. THE MYSTERY OF RADIUM. In the course of an interview with the "Westminster Gazette," Lord Kelvin is reported to have expressed himself as being decidedly of tbe opinion that the source of energy of the heat emitted by radium is not in the clement itself. Ho remarked: —"It seems to me absolutely certain that if omission of neat at the rate of 90 calories per gramme per hour found by Curie at ordinary temperature, or even at the lower rate of 3S found by Dewar and Curie from a specimen of radium at the temperature of liquid oxygen, can go on month after month, energy must somehow b© supplied from without." MANURE FROM THE ME. A Norwegian scientist. Professor Birkeland, the inventor of an electromagnetic gun, has, it is. said, discovered a method of preparing nitrogenous elements which are of use in compounds intended for agricultural operations direct from the air. Ho obtains his results by use of electric arcs of a much greater extent than any hitherto adopted. A company has been formed to work his method, and has acquired a large Norwegian waterfall, by means of which the electricity will be obtained which is to produce the new chemical fertiliser.