Scientific and Useful.

Lake Wakatip Mail, Issue 1524, 26 March 1886, Page 4

Scientific and Useful.

Dr Darling fir di half dram doses of muriate of ammonium the best remedy in neuralgia and toothache, a tingle doee of half a dram being often sufficient. The last report upon in fluence of cccupa* lions on mort iliiy shows thnt vitiated atmosphere seriously affects n o.tality, nnd thnt the differences in death mte in different trades correspond to the differences of purity of air. Dr Draper of the Meteorological Observatory, is Mid to regard oz< ne as c >nstituting a prcdi'po'ing cause of pneumonia. If this be the cose, the matter of keeping plants in bedrooms becomes serious, as flowering, and especially odoriferous plants exhale ozone large* FIREDAMP INDICATOR. A new fire-damp indicator has been devised by M. Lechien, of Mods. It consists of an indiarubber ring, the internal circumference of which is pie'ed with holes. This is allowed to become indited in a suspected locality, and when it is placed round a safety lamp, a very (light compresM >n sends the gas into the interior, and its < haracter is indicated by the alteration produced in the flinie.

A POWERFUL H.i:MO>TATIC.

A curious and interesting discovery is reported to h*ve been made in Columbia, which, if confirmed, will be va'uable to surgeons. A shrub, which is called there "aliia," exudes a juice which is so powerful a hemostatic that when a knife is smeared »ith it, and used for operating purposes, the largest vessels may be severed without any hemorrhage. A HEW IBLAKP lit THE PACIFIC. B. Qreenebaum, United States Consul in Samoa, in a letter to the Merchant's Exchange of San Francisco, says that an island never before reported has been thrown up out of the sea about forty miles off the Tonga Islands bearing toward the Fiji Islands, in the track of California vessels The island is two miles long snd 250 feet high, and is in latitude 20° 28' south, longitude 17S°2f west. BrRTIVAL OF THB FITTEST. In a paper on the size of the brain in ex tinct animals Profresor Mftrsh of Yale College lias brought forward the remarkable fact that in the race for life during past ages the surviml of any particular group of animals depended upon the size of their brain, as compared with tint of their con'emporaries of the same class. Braim won then, as now, and the brain of animals crushed out of existence was always found to be relatively smaller than that of those outliving them. HIGH OBSEBVINO STATIONS. The Mexican Government are about to establish a meteorological stition annng their highest mountains at an elevation of nearly 20,000 feet above the sea level. Access to such a place n list be always precarious and frequently impus«ible for a long time together. Hence it is necessary to make exceptional provisions for rendering the instruments almost independent of human supervision and attendance. The necessiry apparatus is being constructed, and, as far as possible, all the instruments are being made to go for a year without stopping. THE PBESERVAIio* OF THE OUBLISK. The work of preserving the obelisk at Central Park, New York, has now been completed and apparently none too soon, as the numerous storms which hare since assailed the shaft would have done it material damage had the pores of the s'one still remained open. The process employed was that of treating the heated stone with a mixture of paraffin, creosote, and turpentine. Now that the scaffolding is entirely removed, the stone shows to good advantage ; and, as it is a trifle darker in colour, it resembles more perfectly the original sreni'e. The treatment has had the further effi ct of bringing out the characters into such strong redef that a number have been deceived i-ito believing that they must have been rec.it.

ASCIEXT WOOD CAKVING. Among the papers read at a meeting of tbe Society of Antiquaries of Scotland wbb one on a wood-carver's tool-boi found in a bog in the island of Avis, Orkney, and exhibited by the finder. The box, which measures \\\ in. in length by \\\n. in breadth, and dm. in depth, is elabontely ornamented by a running pattern of diverging spirals, and other designs of Bp"cially Celtic character. The box was furt.iihed with a sliding lid, which is now in fragments, and it contained a series of toolhandles nude of bone or horn, evidently for carving in wood or some such purposes. The blades of the tools, which had been of iron, hare entirely perished, but there remainei in the box the piece of pumice stone with which the carver used to polish up his work. This box is the oldest bit of wood-earring known in Scotland. SEW LIGHTING APPARATUS. The Laewen is the name of a new lighting apparatus, which produces an illuminating gas by forcing air through creosote. It is the invention of Messrs Lyle and Hannay, and consists of a cylindrical vessel capable of containing 30 gallons of heavy hydrocarbon oil. Air under a moderate pressure is conducted t»the cylinder, which is fitted with a special burner having two tubes, one within the other, leading up to it. The inner tube dips into the creosote, and the pressure of air on the latter forces it up the tube. A portion of the air finds its way to the burner through the annular space between the inner and outer tubes, and air and oil combining at the burner form when ignited by a match, a flame which gives a light that is useful for general working purposes over a rxlius of 150 to 200 yards. Tha proportions used to form the prop-r light are four of air to one of oil by volume. The Lucigen has been used at the Forth Bridge Works.

C>StPOBITE PORTRAITS. One of the chief application* of composite photography will be in the direction of producing more reliable portrait* of representative men by combining the testimonials of individual artists. The suggestion that, by combining the individual conceptions of several srtis't, one would obUin a more reliable portrait than any of the compore'.ts, was near at h>m 1. The first such application was made by Mr Galton. He made a composite of six medallion heads of Alexander th» Great, and naturally claimed for the composite the combined authority of all the artis's. In this way Science has recently come into possession ot a new Shakespeare. In the case of Shakespeare the diversity among the several originals is strikingly evident, and thus a composite was needed to give a characteristic, individual, natural faoe. This suggested to Mr W. 0. Taylor the application of the same process to Washington's portraits. He has grouped the several portrai's into three groups, owing to the differences of position of the portraits, and the scent acy of the work U well shown by the fuc that the agreement axnongtt the resulting three composites is very close, while tbs originals ihuv every shade of individual difsMwet, .