SCIENCE NOTES,

Otago Witness, Issue 2086, 15 February 1894, Page 49

SCIENCE NOTES,

— A new explosive, invented by Dr Ochse, who was formerly connected with the Krupp works, has caused a fall in Dynamite Trust Bhares. The new invention consists of an explosive gas cartridge formed of a glass tube, containing a few grammes of water, which, by electricity, is conveyed through a platinum contact a:.d is decomposed in*o elements of vapour oxygen, which produce aa explosive gas. The pressure can be produced according to reqaiiements up to 5500 present atmospheric pressure. The experiments which have already been made by the military authorities with tbe new explosive have been successful, and show that it possesses the quality of 3afety, and that it is far reaching in its effect. — Mr Eirkpatrickj of Winona, Minnesota, has been trying a series of experiments to discover whether mental images are really formed in response to words. He requested his class to write down what came into their minds on hearing 10 ordinary and familiar nouns, such as " book," " church," " man," "horse," "tree," "lamp," and so on. The answers were, so various as to be difficult of classification, but they were roughly divisible into three classes — namely, distinct images, showing size and colour of the object ; secondly, particular individual instances of the object ; and, thirdly, indistinct images. Distinct images occurred to three-fourths of the class, but probably the conditions were especially favourable to distinct conception. In a subsequent experiment on 200 normal students with less forewarning, the proportion who had distinct mental images was 10 per cent, less, and in the case of 400 school children still less ; but many of the children did not understand what was required of them. The results indicate that in reading there is at least a tendency to form distinct mental images, and especially in the case of females, — A wise and important step ha? been taken by Dr Herman B'ggs, of New York. He has officially declared the contagiousness of consumption, and recommended the Board of Health to adopt measures for the prevention of the Bpread of the disease. Dr Biggs suggests that the public should be educated by means of circulars and other publications to realise the importance of preventive measures. Farther, it is proposed that persons suffering from chest affections, or their medical men, shall be required to report to the Board of Health where tbe disease exists, that proper instruction may be given in re3pect to disinfection. It is considered undesirable that pulmonary complaints should be excluded from the general wards of hospitals, and that distinct hospitals for consumption should ba encouraged. IE these measures are regarded as of such necessity in America by health authorities, how much more strenuously should they commend themselves for adoption in our metropolis ! Here pulmonary complaints are rife, and it is commonly said that something to lessen the chances of infection should be done, but no scheme, such as Dr Biggs's, has yet been formulated amongst us, and considering that its success depends much upon education, no time should be lost in commencing a method of necessarily slow attainment. — The Hospital. - —An American agriculturist, F. L. Stewart, has published in Science an account of a most important discovery which he made some years ago and has followed up since relating to the great value of maize as a sugar plant if properly managed. The Bugar in the juice of a maiza plant increases steadily until the ear is thoroughly formed, but then as the ear ripens the cugar falls off rapidly towards nothing at complete maturity. This sudden failure in the sugar supply of the maizj plant ia what discouraged previous investigators of its value as a rival to the sugar cane. Bab Mr Stewart observed that in certain plants in which no ear formed or from which the ear had been removed the sugar supply, instead of falling off as in the ordinary case, goes on getting richer and richer till a juice is reached which contains 15 per cent, of cane sugar. But this is not all, for the grain can be allowed to form without prejudice to the final sugar supply, only if must not be allowed to harden ; thus the grain can be gathered in the shape of sugar corn for canning, or used for cattle feed in the form of ensilage, and in this way a double crop is derivable from the plant — first the immature grain and second the sugar. With this treatment maiza seems to have the promise of great advantages over sorghum and beets as a sugar plant, and Mr Stewart claims that in the suitable parts of America not only would a ton of maize cost only half as much to raise as a ton of beet, but it would have the great advantage of its yield of graiD, and better fodder value of the residue after crushing. If it is remembered that hitberto the maize has been selected and developed quite irrespective of its value as a sugar plant, there is no saying how splendid an annual sugar cane might be made of it by a few years of skilled horticulture. It is an interesting fact, pointed out by Mr Stewart, that the sugar cane produces hardly any seed, whence its power of storing such quantities of sugar in its juice ; th 9 maize deprived of its seed Becomes practically a sugar cane. — One of the most interesting novelties in the construction of the great Memphis bridge across the Mississippi, at Cairo, was the use of mattresses to protect the river bed from scOur under the pier sites. These mattresses were woven from willow withes and wire. They were 400 ft loDg by 240 ft wide, and were sunk by loading them with stone. When in place they completely protected the river bottom from scour, aud enabled the pier caissons to be handled and sunk without difficulty. Each of tbe mattresses contained 1000 cords of brush and poles, 900 tons of Stone, aad 10,0001b of wire.

— Experiments have lately been made showing the effect of the colour of glass bottles on liquids contained therein. It has bßen proved that liquors contained in colourless bottles, which have been exposed some time to the light, acquire an unpleasant taste, and this, too, even though they may have been of superior quality before treatment. On the other hand, liquors in brown and green bottles remain unchanged in quality, even if exposed to stroDg sunlight. The experiments proved that these results were due to the chemical action of light,

and that in conseqaence red, orange, yellow, green, or opaque bottles should ba selected for the preservation of liquors, while white, blue, and violet glass should be avoided.

— The eggs of insects have greater powers of vitality than any others. A case was published of an egg producing an insect 80 years after it must have been laid, and the scientist responsible for this statement thinks the power of vivification may endure in these egga for an indefinite period. Many eggs of insects are exposed to the air without any covering, and many are sheltered too slightly to be Becure from the frost. Tnis, however, they are able to resist, re* maining unfrozen though exposed to the severest cold, and recovering their vitality even after having been frozen into lumps of ice. On exposing several silkworm eggs for five hours to a freezing mixture which made Fahrenheit's thermometer fall to 38deg below zero, Spallanzani found that they were not frozen nor their fertility in the slightest degree impaired. Others were exposed to a degree of sGdeg balow zero without being injured. The quality of tbe eggs' of snails is, perhaps even more marvellous. These egg?, if desiccated in a furnace until they are scarcely visible, will always regain their original bulk when damped, and the young will be brought f ortb as though the eggs had never been in any way Interfered with.

— There is a certain Greek engineer, now resident in Europe, who ought to have been an American (says Electricity), for he is the author of just the kind of scheme that, in the matter of boldness and picturesqueness, the world at large looks to Yankeeland to originate. At various points on the Bosphorus the current from the Black Sea to the Mediterranean has prodigious force, and ie is now proposed to harness some of this waste power for the lighting of the city of Constantinople and a considerable length of tbe adjacent coast by electricity. The way in which the inventor intends to turn the ocean currents to account is to erect three very powerful dynamo matihines upon the three points of the Bosphorus where the current has the greatest force, and, so far as can at present be learned, the project appears to be practical and realisable. It is stated that a company of capitalists has been formed, the necessary funds subscribed, and application for a concession addressed to the Turkish Government. Ib is understood that the Government has taken the project into consideration, and has nominatel a commission to report on it.