SCIENCE NOTES.

Otago Witness, Issue 2809, 15 January 1908, Page 76

SCIENCE NOTES.

—An investigation has recently been made to determine the absolute sensitiveness of the ear. By experiments with a telephone and alternating- currents of frequencies 250 and 500 per second determinate pressure variations were produced at the ear. The telephone was standardised By steady currents, and the relation between current and pressure ascertained. The experiments lead to the conclusion that the normal ear can respond to a pressure variation of about four ten-millionths of a millimetre of mercury.

— A st-«tion of steel pavement has recently been laid in the Rue- St. Martin, Paris, to test its usefulness. The steel blocks are nearly 7in long and 1 l-3in thick, and are ridged on both sides. They are laid in cement so that the tops of the ridges just reach the surface. The^ ridges are so close together that a horse's shoe covers at least three ranges of them. Jt is believed that such a pavement will prove superior to asphalt in bejng less slippery, and more durable than a pavement cf wooden blocks.

— The industrial use of the whale involves a wicked waste of material. For instance, from- a right whale 50ft long may be obtained 250 barrels of oil and perhaps a ton and three-quarters of whalebone. The remainder of the vast carcase, some SO tons, i 3' thrown away as absolutely worthless. There seems to be a gold mine here for anyone with the enterprise and capital to work it. The hide of one whale, spread out, would cover 1500 square feet, and when tanned makes excellent gloves and leather.

— That the earth is gradually drying up is the conclusion reached by the French geologist M. Martel. He has made careful observations of subterranean caverns. They contain, he says, not only the secret of prehistoric life, inasmuch as' they were the homes of men of the remotest age, but also 'bear indications of the endless future., M. Martel has found proof of a steady fall in the level of the water in these subterranean depths, and from this fact he concludes that the world will eventually become depopulated through the failure of the water supply, and finally become a dried-up planet. — Professor Koch regards sleeping sickness as an onormoas danger to the whole of East Africa. He finds that the tsetse fly, the Glossina' palpalis, which conveys the disease, breeds not only on the lake shores, but along the whole length of the rivers. Professor Koch" considers that there is x a •distinct connection between crocodiles and Sleeping sickness. Wherever crocodiles are found the disease may be discovered, but *nly in places near the water. The blood $f crocodiles forms the chief nourishment *f the Glossina, which sucks the blood boilween the plates of the animal's hide. The Extermination of the Glogsina is impossible, put it i-> suggested, that the same end may 90 leached by destroying the crocodiles (far by the removal of the bushes and ufidergrov/th where the animals lurk. — Tho- reason *vhy snow is white is that 'Jill tho elementary' colours are blended together in the radiance that is thrown off norn the! surface of the crystals, which may %c examined- in. such a way as .to detect pheee colours before they are mingled together to give the eye the; -impression of irhiteness. The whiteness of the snow is *lso in come degree referable to the quantity of air which is left among the frozen particles. Considerably more than 1000 distinct "forms of snow crystals have been •numerated. , These minute crystals and |>risms reflect all the oomppund raye of trbich white, light consists. Pink and ?&ri•us other tints may be.^een reflected from •heets of snow under certain angles of sunshine. ' So much light is reflected by snow in the day that the eyes often suffer from it. and enough vs iziven in the night to guide thft traveller, in tho absence of moonlierTit. '

— Among inventions patented by women in- America in the. last few years are a lock{■with 3000 combinations: a letter box for She outside of houses which shows a 1 signal when there is a letter inside for the postjnan' to collect, an improved canteen, an apparatus" for removing* wool from skin by eleotrioity,- a speedy and profitable proper for horseshoes, a new aluminium solder, improvenaents in harnesses, and vehioles, and a buttonhole-cutting machine, by which the distance' between the buttonholes is measured automatically. Nbthintt could be more, divergent than the subjects/ ■whjch have engaged women inventors during any two consecutive months of last year^r The list runs through alarm qlocks. a .fire escape device, a brake for vehicles, a fruit press', a caraet stretcher, a syetem of ventilating , buildings, a barrel-tapping and emptying device, a hammer guard for firearm 3. & bottle-filling apparatus, and an invalid: chair. -

— A Manila^TOpe, properly laid and lubricated, is as strong, weight for weight, as steel; 'that is, a steel rod weighs about eight' times as much as a Manila rope of tha cam» diameter, and has about eight times the strength," the strengths being proportioned to 'the -weights. When used for transmission purposes, it has been found that a Manila, rope Kin in diameter is equal to a double leather belt i 5-Sin in •width, «6 that three such ropes are very nearly equal, to an eight-inch, double belt. 'A two-inch rope, says Cassier's Magazine, •will transmit as much power as a 10-inch leather belt, while the loss from stiffness and creep is estimated as only about onehalf with «he rope >what it is with the belt.

— Barbed wire, which is used in most warts of fcbe -world, was discovered by accident. Jlr-EUwooi^ the inventor, lived, in Tais .nQufch.in a M»&11 town in the United States. Staving a neighbour whose pigs "trespassed on bi« gardes, he put up one 'day a, wire fence of .hia own make. The 1 fence had baxbf and points 1 on it ; it was queer and ugly, out it kepi out the pigs. It was a real barbed-wire fence, the fir«f In the world, and there were, millions of 'inonev »n It, but young Ellwood and his friends only laughed at its strange appearsnoel On©, day two strangers saw this fence, realised its value, and ordered several ton« of tt from Ellwood. Furthermore, they .contracted to sell for a long term of years all the- barbed wire he could produce. Ellwood borrowed £200 and set up a little Factory. A. few years later on he had paid back that loan, and afterwards accumulated an immense fortune.

—Mr P. O. Hanna, the United States Consul at Monterey, in a report to the 'W.ishinaton Bureau of Manufacturers, states jthat a fluid invented by s Monterey man,

and manufactured in that city, .designed for the purpose of cleaning steam boilers of fecale or preventing the formation thereof, is meeting with great success. It is said to effectually remove scale from, boiler tubes, and that it works no injury to the tubes or to the boiler shell. The compound, which has been introduced into various countries in America and Europe, is manufactured wholly from vegetable substance from plants found in Mexico, and is developing into a large local industry. It has come into almost universal use in that country with all industries that use steam boilers, yet the greater portion of the product of the factory goes to the United States and Canada, where boiler users seem to find it a successful solvent and preventive of calcareous scale in boilers.

— The contention that Fiji and contiguous islands are remnants of a lost continent is suppoited by the investigations of Dr Woolr.ough, of the Sydney University. Recently hi spent several weeks in Fiji, when, he directed special attention to the occurrence of granite recorded by Kleinschmidt some years ago. The main difficulty in the way of reconciling existing condition: with on original great area was that depths of 2000 fathoms occur between the islands under notice. The Solomons and other islets were undoubtedly the visible links in the chain which ended at New Guinea. Bug against this theory had to be .placed the in-raens? volcanic an-3 coral areas of Fiji, which were of more recent origin than the recks forming the basic fabric of the continental area. It -was necessary, therefore, to look for land evidences of faulting or breaking to account for the submarine depths. The granite area in Viti Levu was found to be from 400 to 600 square miles in, extent, underlying the modern volcanic rocks. He was, however, unable to determine the relationship between the granites and slates, although he traced the lines of junction to some extern;. A ranr^i of granite mountains with precipitous cliffs on each side gave evidence of heavy faults, creating chasms of great depths. He found the rivers formed a marked rectangular network, an upraised coral reef 200 ft above sea level, conglomerate -rock showing seashells at a height of 800 ft above the sea, certain earth fcilts and tuffs which had 1 formerly been submarine and were now at a height of 4500 ft. ' All these indicated a tremendous uplift, sufficient to cause greater faulting in the original continent. The rivers of Fiji were of comparatively youthful development, and even at present passing through their can yon cycle. Many beautiful examples of hanging valleys were observed.

— Some idea of the way in which motors destroy the nrain roads is given in the report of the Kent county surveyor, Mr H. P. May-bury- "In many of the home counties," he says, "costs have gone up from 50 to 60 per cent, in three years, and are still increasing, and the surveyor has no hesitation in stating that at least £10,000 per annum of the_ road expenditure in Kent is now due to motor-car : traffic. It is estimated that in the current year (1907-08) at least £6000 will be expended upon dustlayinp; alone. The high-speed traffic has a prejudicial effect upon the road surfaces, and as at least 60 per cent, of the cars are now fitted with, armoured tyres, much greater damage is caused than formerly. The steel studs and bands minimise, the risks of slide«slip, of punctures, and -wear of tyres at the expense of the roads. The evil is increasing, and heavy expense is being caused to road authorities in repairing the rufs caused by motor-cart-in an otherwise good surface- On the rural main roads (which suffer most owing to the high speed attained in the open country) the county surveyor reports that it is impossible to keep the material tight. The chipnmgs ordinarily used to bind the surface are lost in & few days, and nothing but tarred macadam will suffice. The cost of this additional material and the cost of tar painting to abate the dust fall at present entirely on the ratepayers of the districts through which these rnptor cars travel." — A very large irrigation scheme is now in process of development in Egypt. The area of land under preparation for irrigation and cultivation is about 125,000 acres ; it is bounded on the west by the Nile, and to the eastward is the desert. It ie almost midway between Assouan and Edfu : the soil is dry and parched, and is supposed to have received no water for the last 3000 ro- 4-000 year 9. It is, moreover, saline, and for this reason it is necessary to wash the ground for from three to four weeks before any crops, can be grown upon It. When first wetted, the ground swells and rises about 6in. afterward subsiding: from lft to 2ft. The east bank of the Nile at KomOmbo -i& too hijrh to a 1 low of the land being irrigated at flood time in the usual manner, and in order (o obtain an adequate supply of water for the continual watering of thi<» large tract of land it was necessary to pu"t down ; sets of powerful and sDeoiallydesigned / pumps. These pumps lift the water through suction mains 64ft in diameter, and discharge it into riveted stee.l rising mains of the same capacity, which in their turn deliver the water into a service reservoir. A largp steel canal starts i from this service reservoir, and delivers the ■ 'water into distributing earth canals or cul- : verts, from which it flows on to the land. The lift of th© pumps is from 16 to 2& yards, and the top of the reservoir wall is 115 yards above sea level at Alexandria. The service reservoir is made of reinforced ' concrete. The canal is composed of riveted steel, the plates being iin thick. It is nearly semi-circular in form 1 , 6* yards in i diameter, with 20in straight aides at the top. beinsr therefore nearh- 12ft deep. Its ! total length is nearly a mile. A POPULAR AUCKLAND SKIPPER COMPLETELY CURED BY BHEUMO From Auckland, on July Ist. 1907. Caotain J. G-ibba writes: — "I was incapacitated for eight months, and could ncl, go to sea ; in fact. I was bent double with pain. I tried Rotorua. for three months, and came back, not having received any benefit. Nothing seemed to do me pood, until a friend of mine, who had also taken Rheum o, asked me to give it » trial. The result, after taking four bottles, surprised both myself and my friends, who knew how Tnuch I had suffered. I shall recommend your medicine to anyone who suffers with rheumatism or gout." Give Rheumo a. trial, and it -will cure YOU. All stores and chemists. 2s 6d and 4s 6<3. — Jaggles : ''Do you think there will ever be any radical change in the style of men's hatsV" Waggles: "Not unless somebody invents a hat that will cover the bald spot on the back of the hea*L"