Scientific Notes.

Otago Witness, Issue 1581, 4 March 1882, Page 29

Scientific Notes.

Tne Study of Thunderstorms. Studies of special phenomena have become vety popular since it has been found that valu able results ate often obtained in this way. Recently, a French gentleman"- M. Lespiault, by name—has been studying the snbjeet of than der'Btormß In the Gironde, and comes to the carious conclusion that valleys are more struck by bail than hills or table land. It seems fchajt a certain depth below the clouds is necessary < for the formation or the fall of bail to occur without obßtacle. Further, the direction of the valleys traversed have an immense ir fluenoe on the direction of the clouds, though they only cause a momentary deflection, and the clouds, after following them a certain time, are carried on in the general direction of the ver tical movement. For example, if a valley be In the axis of the zone or hail, or a little inclined to that axis, the hail clouds seem to be carried along that valley as dead leaves are carried along by the wind in a trench. If the valley be subdivided by a mountain spur into two others, the hail cloud also divides and the two secondary yalleys are ravaged in their turn, at least to the extent in which they are within the jsone of haiL Valleys lying across j this gone have ajso an influence, though less marked. When the clouds paps over them they show a tendency to descend and to spread out on the two Bides of the ?one, so that the zinc is broader over valleys than over plateaux, ; and the ravages are often greater. Jt might hava been added that this was to be expected, since storms and air currents of all kinds generally follow the depressions of the earth, being guided by the hills to a very great extent. Drainage by Electricity. The first extensive application of electricity for mechanical or engineering purposes is about to be undertaken in Mexico, in connection with engineering operations having for its object the draining of the great water basin in the centre of which the city of Mexico is situated. The plan in brief is to establish on the western slope of the mountains, where the fall is great and rapid, a number of water wheels sufficient to develop some 20,000 horsa-power, and make them drive dynamoeleotric macnineß of high electro-motive power. The current from these machines is to be conducted about 20 miles to a let of electric motors placed on the margin of the lake, and driving pumps, which will require about 7000 horse-power to work them. Toe water has to be raised about 40ft. to clear the ridge, but once raised it has an uninterrupted fall toward the Pacific of several thousand feet, 00 that the descending water in made to add to the power required for keeping up the work. The whole apparatus constitutes what Mr Maxim calls *n ' electric syphon,' Thl» plan obvJatw tbe necessity tot exteuejyc blasting

operations, and, it is believed, will Bucceed, arid thus relieve Mexico from the inundations that have damaged it so much for several centuries. The Moon and the Weather. M. De Parville has published in the Journal dcs Debats, a paper on the fcemperatnre of the past year, which, at Paris, has risen to a height exceeding all previous authentic records. In the course of the article he raises the question as to whether the dryness of the past summer could have been foreseen, and answers it in the affirmative. Having then referred to the Influence of solar action on the atmosphere, he says : ' A very long Beries of ©bservationa has also shown that the moon, which passes every month from one hemisphere to the other, influences the direction of the great atmospheric currents. The changes in these currents in consequence of the prevailing moisture or dryness atu intimately connected with the relative position for the time being of the sun and moon, i The distance of the moon from the equator, that is, the inclination of the moon's path to the plane of the equator— varies every year, passing from a maximum to a minimum limit ; and the meteorological character of a 'series of years appears to be mainly dependent upon the : change of inclination when these extreme limits i have been touched. Observations prove that ; the rainy years, the cold winters, and hot sum- ; mers return periodically, and coincide with ocr i tain declinations of the moon. In our latitudes the rainy years occur when the moon's declination has touched its extreme limits of 28 1 eg., 26 1 eg., or 18deg. respectively. They are sepa r rated from each other usually by periods of \ about three years, and then six years.' M. de , Panrille then gives a list of rainy years running I back to 1783, the most recent being 1879, 1876, i 1866, 1859, 1856, and 1853. in each of which , the moon's declination was either 28deg.. 26deg., t or 18deg., beginning with 26deg. in 1879, and , running back in the order named. The severe 3 winters, he says, coincide as a rule within a year of the same declinations. The dry sum> I mers come naturally in the middle of the period } which divides two wet years. The next wet } year ought to coincide with the declination of 18deg.. therefore, with the year 1884, as the last was 1879 with the declination of 26deg. Between the two years comes the period of maximum dryness, and it may be expected, there- ' fore, that the year 1882 will be another dry <; year. [ Odds and Ends. r By securing variety in temperature, through 1 planting oysters in different depths of water, as 1 practised in Connecticut, the Scientific Amerit oan says oysters can be obtained in a fit con- . dition for the table every week in the year, t The greater the heat tbe earlier the oysters t will spawn. Those in the deeper and colder i water feel the heat later and spawn later. Some | portion of the oyster field, so to speak, will ) therefore be ready for harvesting at all times. Hollow Steel Shafts for Steamships.— Among . the recent improvements introduced in England 1 in building large steamships, are hollow ateel i shafts, which are chiefly manufactured by Sir r Joseph Whitworth and Co. On this system a i 10 inch shaft has a hole 4 inches is diameter, f reducing the weight 16 per cent., while the > strength is only diminished by 2.56 per cent.i With a 5-inch central hole these figures would : be 25 per cent and 4.25 per cent, respectively.' The New Tay Bridge.— The total length of the new Tay bridge in Scotland, which will take the .place of the ,one which went down with Buch terrible loss of life, will be about. 10,000 ft., or about two miles. The bridge will 'ie built strong eu6ugh to resist more than twice the force of the hardest gale that may sweep against it. The wind-preßSure is placed at 2llta ncr square foot, and allowance is made Tue Pall Mall Gazette sayß :— 'The first practical application of stored electricity to the lighting of interiors has taken place in the Junior Carlton Club. The room is ordinarily lighted by a modified form of sun burner, with about 25 gas burners hi it. Beneath this has been suspended a shade somewhat like the shade of an umbrella, and in this 15 British > incandescent lamps are placed. The electrioity came from accumulators which were placed in ' the basement of the bnilding. These had been charged with electricity at the Hindon street works of the British Electric Light Company, and had been brought into the dab only a few ' hours before the lighlingup took place. The accumulators used are on the IWe principle, and were sufficiently charged to last about six hours. The experiment is said to have been - successful.' , _ , An Austrian engineer named Lauer has disie covered a new method of disintegrating rock, i The chief feature of his system is to employ a 9- hollow cylinder, like gas pipe, and to place the y dynamite cartridges, not as hitherto in a hole i bored into the rook to be blasted, but in the ie cylinder in question. The cartridge only k touches the surface of the rook it is desired to it shatter. The explosion of the dynamite is y effected by electricity, and the effect is said to ir be greater than with the usual cartridge in a if hole bored in the rook. The rock is shattered ie into fragments so small that a fair stream is y able to wash them away without help, whereas c in case of gunpowder, the rock is only Bplit up c into blooks more or less large and troublesome r to remove. The Lauer system is calculated to c save fully 40 per cent, aa compared with the i- oldßystem. c Though superior to ordinary, toughened glass c has never yet taken its place, which 1b no c doubt largely due to its extra cost. Mr 0 Frederick Siemens, however, now proposes c adapting the toughened glass made by his ir process to the manufacture of lamp posts, c water mains, &o. His glass, he says, is 8 stronger than iron castings, imperishable and s incorrodible, and though the price per lb is a twice that of iron, the specific gravity is so d much less that the user will be able to obtain c glass articles at about 3 per cent, less than the :, same goods in caat-iron. Mr Siemens pro* ;t crises this, but it does not by any means c necessarily follow that he will perform, as it is U no easy matter to upset the long accustomed c use of materials. ,t The Nautical Magazine of London baa been tracking American storms across the Atlantic, and finds that 63 per cent, of those starting in tb gountry reach Great Britain. As it takes j them federal days to make the voyage across t the ocean, tbe proposed international exchange ti of meteorological reports by cable ought to en. a able the inhabitants of England to know very a nearly what sort of weather they are going to c have, c Of late considerable attention has been di3 rected to the curative properties of the eucajpp, 9 tvs, and it would seem as if its medicinal vir. 3 tues are almost unbounded. As a means of 1 relieving catarrh, its effects are certainly most c pronounced, and we (Ararat Advertiser) are a informed by a gentleman of undoubted authof rity that in tbe case of difltemper in dogs it is c exceedingly efficacious. The cure is Baid tobe c complete and rapid, the mode of administration c beiug 8B f llowa : — A<J soon as the disease is ob* d served, t ake two or three young leaveß and chop ;, them finely with a little butter and make into o a bolus, which can be administered without :. much difficulty. Some milk and sulphur may r then be Riven, and the following day a dose of a castor oil, when no further treatment will be g necewftry, j