NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXVII, Issue 8360, 13 September 1890, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

ELECTRICITY IN THE NIZAM'S DOMINIONS. According to Indian Engineering, the Chudderghaut Municipality have received a proposal from Mr. Harvey, the representative of Messrs. Semens Brothers, tho well-known electricians of London, to light the whole of the streets within the municipal limits for a yearly payment of eleven thousand rupees. The firm offers to put up thirteen lamps for every twenty at present in use lit with kerosene. If the terms are accepted the Municipality would effect a saving of between three or four thousand rupees a year besides having the streets much better lighted. The proposal was to bo considered at tho next meeting of the committee NKW USES FOR ALUMINIUM. One of tho many fields of usefulness of aluminium is in the manufacture of ship plate. Ten per cent, of it added to iron makes a plato of great strength, taking and retaining a high polish and possessing the eminently valuable quality of being absolutely proof against tho corroding action of sea-water and the adherence of seed-grass, barnacles, and other similar Growth. Gunbarrels can also be made of this alloy that will neither rust nor lead in use. MALARIA. Somo of tho peculiarities of malaria aro pointed out by Mr. Stanley in a way which will surprise many who have adopted preconceived notions about ibs mode of operating. In sailing up tho river with the wind, malaria is comparatively harmless ; while in sailing down with tho stream and against the wind, it is particularly deadly. During a calm or under shelter from the wind there is safety, while danger ensues from giving free admission to a breeze. Even a veil or mosquito curtain affords considerable protection. Local malaria is less dangerous than that which has been transported from a distance. Trees, tall shrubbery, a high wall, or close screon interposed betweon the dwelling-placo and the wind currents will mitigate their malarial influence, and tho inmates will only be subjected to local exhalations. Fcrty miles of lake water between a camp and the opposite shore are no positive protection against the transportation of malaria, while a thousand miles of river course may serve as a flue to convey malaria in a concentrated form. A house in a forest is protected from the invasion of malaria, bub in the open country neither a houso nor a tent is sufficient protection, sinco the air enters by the doors of the house, under the flaps of the tent, and through the ventilators, to poison tho inmates. The strangest peculiarity of all is that tho virulence of the malaria seems to increase with the height above the sea—an idea very different from that which is usually insisted upon. Stanley says that at Banana Point, which is at the sea level, ague is only too common ; that at Soma, 80 feet higher, it is more common still; that at Vivi, where the station is 250 feet higher than Boma, without a swamp near it, there were more cases than elsewhere; that at Stanley Fool, about 1100 feet above sea level, fever of a pernicious form was prevalent; that on tho Nyanza plain, 2000 feet above the sea, the party were laid up with severe attacks ; and that on the plateau of Kavalli and Undussuma, where tho average level of the land was over 4500 feet above the sea, Messrs. Jephson, Parke, and himself were successively prostrated by fever. All these facts are very remarkable, because they seem to show that malaria is concentrated by being diffused and scattered, whereas the very contrary is what might have been expected. It almost seems as if this crescendo of horrors had been compiled to excite surprise and invite contradiction. The independent opinion of Dr. Parke should be of value, but that has yet to be given. He may be able to offer some explanation which would reconcile divergent testimony. FORCED DRAUGHT. Forced draught is coming to bo looked upon with disfavour in the British navy, owing to the many breakdowns which have attended its application on shipboard. It is said that a trial trip mado under forced draught does more injury to the boilers than four years of ordinary use. Moro recently, however, the Admiralty has authorised a series of experiments with forced draught on shipboard with locomotive boilers. The plan proposed is this : Instead of forcing the air through the furnaces by means of fans, there will be established induced draught. The plan is to operate at the root of the funnel by a fan acting upon the products of combustion, and so fitted that it may be used to accelerate the draught to any degree required. The arrangements in the boiler-room are not interfered with, the driving gear taking the place of the highspeed engines now used for forcing air. One thing that the steamship City of Paris conclusively proved was that forced draught on the stokehole system can be efficiently maintained at sea.

SUCCESS IN CELESTIAL PHOTOGRAPHY. Professor W. H. Pickering reports that the South American party, now engaged in celestial photography in connection with the " Draper Memorial" work, have succeeded in getting a number of photographs of the planet Mars. They were taken on two evenings, April 9th and 10th ; seven negatives on each occasion, and at times so chosen that the planet presented the same face in corresponding pictures on tho two evenings. The pictures show the spots and markings on the surface of the planet very clearly ; the most interesting thing, however, is that the negatives of April 10th show the southern snow-capdistinctly larger than those taken the evening before. There can hardly be a possibility of mistake in the case, because all the seven pictures of each evening tell the same story. There must have been a heavy snowstorm on that part of the planet between the two dates.

USES OF ELECTRICITY IN AGRICULTURE. From the results of a series of experiments that have been undertaken in Russia by N. Specnew, extending over a period of five years, it appears likely that electricity may eventually play a very prominent part in agriculture. The experiments showed that by submitting different seeds to the action of an electric current their development is rendered more rapid and complete. The seeds of haricot beans, sunflowers, winter and spring rye were used. A second series of experiments was made with pot herbs and flowering plants at Kief. The influenco of the electrical treatment was shown by a larger crop and by the growth of vegetables of enormous dimensions. In a third series of experiments electricity on a largo scale was applied, static electricity being used instead of current electricity. The results were quickened ripening and larger growth. Barley ripened twelve days sooner with electro-culture. Potatoes treated in the same way seldom showed disease, only 0 to 5 per cent, being bad, instead of 10 to 40, which is the usual percentage. An important factor in this treatment, is that vines which have boon subjected to it possess immunity from phylloxera, and this points to a new means of combating the microscopic diseases which attack vegetable growth. It is suggested as a weapon with which to fight the potato bug and the army worm. The cost of the process is comparatively small. MISCELLANEOUS. A new method of towing ships has been invented. The object of tho invention is to prevent undue strain on the cable in rough seas. This is accomplished by fastening the rope to a drum connected with a piston and cylinder. Any extra strain causes a revolution of tho drum, which compresses the air in the cylinder, and the cable is thus payed out and hauled in automatically, according to the tension upon it. A now book-marker is patented by Mr. Lanchester. Clips are fitted on to the covers; a strip of silk ribbon connects them. When the book is open the ribbon is extended, bub on closing it the ribbon falls between the open leaves. Dr. Dennys has been granted a patent for a lock-nut washer. The washer is made with a sma'l projection on its face which is iatended to fit in a hole, to be made with a centre-punch, in the stud on which it rests on one side of the washer. A flat plate extends, which is to be bent square up when the nut has been tightened, thus preventing it working loose. A useful article for travellers is patented by Mr. Melling, which he calls a damp tester. It is a small gelatine star, which if placed on anything damp immediately curls up, thus readily detecting damp sheets and seats. It can be used any number of times, as it flattens out again when removed from the moisture. Another lock nut patent granted. The base of the nut is not at right angles to the axis of-the bolt hole, so that when the nut is screwed up tight the end of the bolt is slightly bent, which prevents the nub working loose.