SCIENTIFIC AND USEFUL.

New Zealand Graphic, Volume X, Issue 7, 18 February 1893, Page 152

SCIENTIFIC AND USEFUL.

Dresses may be rendered incombustible by dipping them in a solution of tungstate of soda, one pound in two gallons of water. The most delicate colour will not be affected by it. SALT AND LEPROSY. The excessive consumption of salt, notably in the shape of salt fish as a general article of diet, is stated to be conducive to the production of leprosy, and at the Pau Congress some evidence in support of the statement was given. In the Antilles, for instance, the blacks have salt fish—cod from Newfoundland—as a daily article of diet, and leprosy is more prevalent amongst them than amongst the whites and half-breeds. THE LARGEST NEWSPAPER. The largest newspaper ever printed was published in New York, July 4th, 1859, and bore the extraordinary title of The Illuminated Quadruple Constellation. It contained portraits of President Buchanan, Henry Ward Beecher and Elizabeth B. Browning. It was only issued once, and considering that the 28,000 copies printed contained enough paper to turn out 6,000,000 copies of an ordinary-sized £d newspaper, this may be fairly considered to have been quite enough, for some time. BUILDINGS OF SAWDUST. Extensive experiments have been made in Germany with sawdust that had been treated with acid. The action of the acid is to convert the fine particles of wood into a material that can be moulded into blocks or other form, having an extremely hard surface, and being practically non combustible. The material is said to be stronger than timber and much lighter than either iron or steel, while in point of cheapness it is superior to either wood or metals. Arrangements are being made to manufacture the material on an extensive scale. A NEW MINERAL. A new mineral, not unlike asbestos in its properties, has been discovered in immense deposits in the United States of Columbia. It is stated to be ‘ the colour of amber, perfectly transparent, and incombustible. Experiments made at Bogota indicate that it will be of great value for the manufacture of bank-note paper, for fireproof and waterproof roofing tiles, and for suits for fireman. A white varnish can also be extracted from it, says our informant. The substance has been named • Cucaramanquina,’ and it is expected to prove of greater importance than asbestos.’ EDIBLE CHRYSANTHEMUMS. It appears that the Japanese do not raise chrysanthemums as ornamental plants, but cultivate them as edible ones. It is the flowers that are employed by amateurs. I hose are eaten as a salad after being steeped in water and then boiled. In Japan the flowers of the chrysanthemums constitute a truly popular dish, and during the months of November and December bunches of them, washed and carefully displayed, may be seen in the stores of all the dealers in vegetables. Almost all the varieties are edible, strictly speaking, but those to which preference is usually given are the ones with small deep yellow flower heads, and which are not so pretty as the varieties cultivated for ornament. The Japanese also eat lily bulbs. HANDY RULE TO FIND SIDEREAL TIME. The number of Sidereal days in a year is necessarily one in excess of the number of Solar days. Sidereal time at noon on any given date is expressed bv the same proportion of a day that the interval between the date and the previous vernal equinox bears to a year. This relation between the fraction of a day and a year is easily ascertained, as their subdivisions bear a very simple relation to each other, there being 12 months in a year, and 24 hours in a day ; there are also 60 minutes in an hour, and (about) 30 days in a month. Thus Sidereal time can be ascertained approximately by a short mental calculation according to the following rule: —Subtract 3 months and 22 days from the date (increased by 12 months if needful). Call each month of difference 2 hours and each day 4 minutes. Example : To find Sidereal time when it is noon on August 30th. August 30th is 8 months and 30 days, subtracting 3 months 22 days leaves 5 months 8 days, allow 2 hours for each of the 5 months and 4 minutes for each of the 8 days = 10 hours 32 min. To find Sidereal time at noon on February 15th = 2 months 15 days, add 12 months =l4 months 15 days - 3 months 22 days =lO months 23 days 21 hours 32 minutes Sidereal time. THE SENSE OF TOUCH IN BATS. Bats have an extremely keen sense of touch, probably (says a contemporary scientific journal), the most delicate of any creature, and they are guided in their flight chiefly by this sense. They have been blinded for the sake of experiment, and then let loose in a room where an intricate network of string had been arranged. This network, however, was not touched once by the bats during their flight. In other experiments it has been noticed that they wisely gave a wider berth to such things as a man’s hand or a cat’s paw, than to harmless pieces of furniture. They can also fly along underground, and in quite dark passages, avoiding the sides, even when a turn or twist comes. Their wings and other membraneous expansions are peculiarly sensitive to touch, but they are comparatively small in the fruit-eating bats, for it is the insect eating bats which have to be on the alert in order not to starve, and which need this excessive keenness of the sense of touch. Sight is useless in the gloom, and it appears to be by the minute changes of pressure in the atmosphere that they recognise the approach of their prey.