SCIENCE NOTES,

Otago Witness, Issue 2201, 7 May 1896, Page 47

SCIENCE NOTES,

• . ' The discovery that heal; influences one set of nerve points in the skin, while sensations of cold are received by another set, has been followed by an interesting investigation by two Italian physiologists, whoße experiments seem to indicate that the various tastes result from the exciting of distincc sets of nerve fibres in the tongue. The proloDged application of ice removed the sensibility for all tastes — Bweet, sour, salt, and bitter. Cocaine destroyed— temporarily, of course — sensibility for bitter only. Other substances, such as caffeine and morphia, reduced the power of discriminating between different degrees of biiter. Dilute sulphuric acid bad a peculiar effect, causing distilled water and even quinine to taste sweet at the tip of the toDgue, although the bitter of the quinine was elsewhere tasted as usual. • . • An infinitesimal force manifests itself iv the spreading of a drop of oil over the surface of water. A film 1-30 millionth of an inch in thickness produces marked results, and yet to cover tbe whole 135 acres of painted surface of the Forth bridge with a coat of that thickness would require less than a pint of oil. It would appear inconceivable that such a^ membrane could in any way affect the ocean in a storm, yet when, in the winter of 1891, Admiral Puvemlle'a ship, the Naiade, was caught in a cjrcloaein the North Atlantic, and a greasy touch was given to the waters by rigging out two coal sacks, each filled with about 111b of tow and lgal of colza oil, whioh latter required renewal only every six hours, the scientific and trained observers on board the French warship reported the result to be a remarkable practical success, tbe oil taking effect upon the dacgerouß breakers due to horizontal translation produced by the wind, but, of course, leaving the swell unaffected.

• . • A new kind of nczzle for fire-hose has recently been introduced into England from the United States, where it is said to have met with much favour. The nozzle is bell shaped, and within it is a ball which causes the jet of water, as it proceeds from the nozzle, to form a.cono shape, which is found very effectivein quenching sre, without oauging the mechanical injury to fittings which accompanies the use of the ordinaryjet. A good deal of wonder has been excited by the circumstance that, although tbe ball ie perfectly free, it keeps its position in a stream of water at 1001b pressure without flying off into space. The same surprise was excited many years back when it was found that eggshells, indiarubber balls, &c, could he made to hang in mid-air by the action of a jet of steam, and experiments have more recently been made iv connection with compressed air which give precisely the same results; Faraday long ago gave the true explanation whence showed that the issuing jet of steam under pressure causes induced currents of air to press upon it from all sideß, and it is these which are able to support solid bodies submitted to its influence, The aotion of the ball in the water-aozzie may doubtless be explained in the same way. • . • It has frequently been found in large factories where the rooms wera broad that insufficient light was obtained on either side between the windows. It has recently been discovered, however, that if the glass used in the sashes be ribbed or corrugated instead of flat, the light will be diffused much more effectively. Some experiments tried by Charles L. Norton, of the Massachusetts Institute of Technology, with different specimens of this glass, show that about 20 ribs I to the kick give a better effect than a smaller

number. Of course, one cannot look through such windows. At a short distance they appear like ground glass. It has been suggested that, where the employees are likely to object to the loss of view thus occasioned, it might be well to put clear glass in the lower part of the window and ribbed glass in the remaining portions. It seems to be necessary to use panes which are rather thioker than those of clear glass, and, consequently, heavier. On this account it may be well to have the greater part of the window stationary, with a sort of transom above for ventilation. Ordinarily, daylight oomes into a window and strikes the floor slanting, at an angle of about 45deg. A big bright patoh can be seen on the floor opposite each window. From this spot some light is reflected upwards, and then a still smaller portion is thrown down and scattered about the room by the ceiling. But if ribbed glass be substituted for the plain kind the bright patch on the floor disappears. The light is spread out into a fan-shaped, beam, reaching far around on each side. This expanding effect ifl sideways if the fibs run up and tfowb, as they © ighfc to ; but if they run horizontally the diffusion in upward and downward. But the latter arrangement is undesirable, because the glass itself, in that case, acquires abrillianoy painful to tbe eye. The effeotß attributed to the new glass by scientific men are almost incredible. Even direotly in front of the window the amount of light apparently received is almost trebled, and well around' on the side, at an angle of 60deg, it is about doubled. It is not alleged that more light actually enters, but that the distribution is such as to give these resultp, it special light - measuring instruments be used for teats a few feet away. t ' . • A German naval oaptain has invented a new lifebuoy, which seems to make falling overboard at eea a thing rather to be desired than otherwise. Primarily it is a large cork ring of sufficiently levitating intrinsiotivlty to support three persons with their talking ends above water. It is provided with a sort of net to afford support to their feet. Its principal features, however, are electric lights fed by a small accumulator and stored with sufficient electricity to keep the lamp Alight 24 hours. There is also a receptacle for con* taining a supply of provisions and water, an alarm whistle, and a switch for turning off the electricity in daylight. • . * There are several trees and plants in the world whose berries, jnice, or bark are as good to wash with as real soap. In the West India Islands, and in South America, grows a tree whosa fruit makes an excellent lather, and is used to wash clothes. The bark of a tree which grows in Peru, and of another which grows in the Malay Islands, yields a fine soap. The common soap-wort, which is indigenous to England, aod is found nearly everywhere in Europe, is so full of saponine that simply rubbing the leaves together in water produces a soapy lather. ; * . • The possible uses of the newproceßS of photography in determining the existence of secret flaww in metals ia about to bo tested thoroughly at tbe Carnegie works, where a large amount of naval armour construction is under way. Proper apparatus haß been secured, and experts there are now at work to demonstrate whether or not rays will penetrate bodies of metal. If this can be done the importance of this prcess from an industrial standpoint oan soarcely be overestimated. It will be possible to secure an exact knowledge of the nature of the metal of great guns without running the rick of explosion, and the defects in the shafts of ocean steamers oan be discovered before the shafts break and thereby cause loss of life and property, and steel castings used for structural purposes can be accurately tested before being put in place. • . • An inventor is haviug Trailt a machine by which he proposes to revolutionise the present methods of tunnelling, the capacity of thfe device for " sawing ont a tunnel," as claimed, being at the rate of 23f b a day. The apparatus is described as being 12ft long, 4f 6 wide, and 6ft high, and, with the H-horse power engine which runs it, weighs some 63001b. The principle is that of a circular saw. Sixty drill points attached to each of two wheels, 4ft in diameter and Bin wide, ma&e 600 revolutions per minute. The points are £in apart, every revolution feeding £iv, and the enthusiastic inventor declares that it will cut 20ft of a Bix by eight tunnel in a day in fchehardestjrock. The latter, being crushed as iine aa wheat grains, is carried to the rear and dumped in a car. The diill' points weigh one-fourth of a pound each, last fonr day*, and are kept cool by means of a steady stream of water. Three men *re required to run the machine.