SCIENTIFIC.

Otago Witness, Issue 1672, 8 December 1883, Page 28

SCIENTIFIC.

— A simple barometer can be made by filling a pickle bottle within three inches of the top with water. Then fill a clean Florence oiliflask with v water, and plunge the neck as far as it will go into the larger bottle. The water in the flask will rise and fall with the weather, sometimes leaving it perfectly empty eight hours before a storm. — Boston Post. — One of the best methods of obtaining perfumes is by the use of grease. The process is called maceration. The best fat employed is marrow, which is melted in a water bath and strained. While it is still warm the flowers are thrown in and left to digest for several hours. They are then'taken out and fresh ones put in the grease. This is continued for several days. The grease and perfume are then separated by the use of alcohol. Beef marrow is nofc the only substance used in extracting the odours from the flowers. Inodorous oils are also used, e-specially refined olive oil, which is more extensively used in the south of Europe. The process used for delicate plants, such as jessamine, tuberose and cassia, which will not allow the use of heat, is on the principle of absorption. A layer of purified lard and such, mixture is spread on the glass bottom of a square wooden box, and upon this freshly gathered flowers are spread every morning as long as the flower is in bloom. The boxes are kept shut, and the grease soon acquires a very strong odour. In saturating oil, instead of glass bottoms to the boxes, wiro ones are used, upon which cloths soaked in oil aro laid, and the boxes or frames are piled upon each other to keep them close. After the oil soaked cloths are sufficiently charged with the perfume, they are placed in a press and the oil squeezed out. — There are current numerous stories of persons who have been struck by lightning finding impressed upon their bodies figures of trees and ' other objests, having apparent reference to the surrounding landscape. Mr Burt, the editor of a paper published at Summit house. Mount Washington, records a painful experience bearing upon this mysterious and interesting subject. While sitting in his office during a thunderstorm, he was struck by lightning, thrown from his chair, and felt at the same time the sensation of a tremendous blow on the back. Upon afterwards recovering himself, and submitting to an examination, it was found that his back exhibited numerous tree-like j markings, which might, by any one fpnd of the marvellous, be easily transformed into' a picture. But Mr Burt is not so ready to accept such a view of the matter. He says :" As there are no trees upon Mount Washington, it seems to me that the peculiar appearance, must be the result of the blood settling in the smaller vessels." — It s"eems to be a well-recognised fact that human beings cannot exist in a state of health on animal food exclusively for any great length of time. _ Vegetables are necessary to prevent I certain diseases, and to remove these diseases when they have invaded the system. But vegetables can be used as an exclusive diet and yet maintain the body in a state of perfect health. Herodotus implicitly attributes the activity and healthiness of the Persians of his timj to the variety and abundance of fruit and vegetables which they consumed. They had at meals not only several dishes, but several courts of vegetable food preceding a very moderate allowance of solid meat. Chambers says : " I 'col sure that the puniness, infertility, pallor, fetid breath and bad teeth which distinguish some of our town populations, is to a great extent due to their inability to get theße articles of tho table fresh. — The remains of what is believed to be the largest mammoth over exhumed in America ■ have been found by uome workmen, excavating at a depth of thirteen feet from the durface, in a gravel pit at Syracuse, New York. Tbess

relics consist of a tooth twelve inches long, and weighing 25 pounds ; and of a tusk five feet long, weighing 150 pounds. This tusk is not entire, but is supposed to have formed part of one measuring ten or eleven feet long. l ( 'rom the calculation of experts i£ is believed that the creature when living must have been at least fourteen feet high. — Rainbow colours are produced on brass ornaments, such aa buttons, clasps, • aud buckles, by stringing them on a copper wire and dipping them in a bath of plumbate of soda freshly prepared by boiling litharge in caustic soda and pouring it into a porcelain dish. A linen bag of finely pulverised litharge or hydrated'oxide of lead is suspended in the solution, so as to keep up the original strength of the solution. While the articles are in this solution, they are touched one after the other with a platinum wire connected with the positive pole of a battery until the desired colour appears. The galvanic current employed must not be too strong. The colours are too brilliant if they are heated after they have been rinsed and dried. Coloured films are more conveniently produced upon a bright brass by different chemicals, by painting with them or by immersion. For example : golden yellow, by dipping in a perfectly neutral solution of acetate of copper j dull greyish green, by repeatedly painting with very dilute solution of chloride of copper; purple, by heating them hot and rubbing over with a tuft of cotton saturated with chloride of antimony ; golden red, by the use of a paste made of four parts of prepared chalk and one of mosaic gold. — It is claimed that by experiment the Zostera marina, or "wrack," can be made to yield, by treatment with mineral acids, a substance resembling horn, capable of being manufactured into forms, and of receiving colour from pigments. This substance is called " algin," from alga,, the generic name of one common species of sea weed. The crude material can be obtained in large quantities on all exposed shores, and its preparation for ultimate manufacture iB a cheap process. — One of the interesting inventions shown at the recent Railway Exposition, at Chicago, was a cast iron file, the merit of which lies in its extreme durability as compared with the ordinary steel file. Scientists assert that in hardening cast iron brittlenees and want of tenacity increase with the increase of hardness. In the file in question there is from three to four per cent, of carbon, and the tenacity as compared with steel bears a ratio of six to one. Ifc i* claimed for the cast iron that it is a true carbide of iron, whereas steel is an oxidated carbide. One breath of air while the metal is being reduced to a true carbide reduces it to an oxidated carbide.