Scientific and Useful

Lake Wakatip Mail, Issue 1522, 12 March 1886, Page 4

Scientific and Useful

A solution of cyanide of potassium poured into warps' nests will effectually kill them ; it is tho best poison to use for insect-killing.

Children suffering from diarrVoci should be lightly clothed, frequently sporgoJ with cold water, and iced milk should be given thi-m to drink.

THB HIAT OKE MILK BBIOW TIIE BITRFACB.

Mr A. B. Sawyer, an inspector of mines, recently read a paper before the North Staffordshire Mining Institute, in which he estimated that the tempoiature at the dopth of a mile from the surface will bo about 122 degrees Fahrenheit, and that long before that temperature is reached it will be nrce f *arv to use compressed air for cooling and ventilating tho workings. The compressed air will ther, we presume, be first utilised in driving machines lor breaking down the coal. A TFBKISH CAVB. A discovery of a cave has been made by two workmen in a colliery near Tyre in Phoenicia. On entering the cave, there were found four sarcophagi, with relief figures of men, trees, flower*, of a very fine workmanship. By breaking a hole in the wall of the cave, a square yard was reached, with two simil.' sarcophagi, and with a number of earthen and glass vessels. It is supposed that the cave was a burial vault. The sarcophagi will be opened in the presence of the Governor of Damascus. Alt EXTINGUISHED FISH.

A curious fish, named from its shape the tile fish, has apparently been rendered extinct in a very summary fughion. It was dredged up about five years ago a hundred miles east of Cape Hatterns, and was afterwards frequently found ; last summer many ships arriving in New England ports announced that they had sailed over a large area of Cape Hatteras which was covered with dead tile fish, and since then no dredging has brought to the surface a single specimen. It is thought that a cold current must have swept orer tho very limited range inhabited bv tlvs fish, at d so have practically annihilated the nice. A variation of four o • five degrees of tempera* ure is, according to Professor Baird, a sentence of death on deep sea fi»h.

THE APPARENT ENLARGEMENT OF CELESTIAL

OBJECTS NEAR THB HORIZON

M. Paul 3troobant has recently devoted a considerable amount of care to examining the cause of this well-known phenomenon. His experiences lend him to reject the theories most commonly received, that the appearance is due either to comparison with terrestrial objects, or to the "flattened arch" shape ascribed to the celestial vault. Experiments made with pairs of electric sparks in a lofty ball showed thnt if the two sparks overhead were 100 mm. spar', the pair on a level with the eye, and equally dis ant from the observer, needer 1 only to be 81 5 mm. apart to seem separated to i similar extent. Comparisons of various pairs of stars give a similar result, and the following formula was found to represent the apparent sire, 9, of a celestial object at ary given altitude, H, when the size on the horiion was taken as 100:

G = 100 - 10 sin 11. Beside this relation, depending evidently upon some phytblogical effect connected with the position of the head, M. Stroobant found that an increase in the brightness of an orject caused «n ttpparent diminution in ita size, and vice vtrta. The great apparent size of the moon at rising was therefore, he considered, largely due to its comparatire faintness when near the horizon.

IBEB PLANTING IN 70BWAT.

The Norwegian Forest Association, started in 1831, is making very good progress. At present there are about two hundred and fiftj members. The Association's joumil for the current year, embracing some 300 pages, contains a number of important papers by the most eminent Norwegian writers on the subject of fore>ts aud forest culture. A meeting for the discussion of important subjects takes place annually. The question of preserving the old and cultivating the new forests appears to be cjming more and more to the front in Scandinavia, where the Government has now established several schools with plantations for the cultivation of voung plants. In Sweden the children of the' rural Bo*rd schools are often employed on fine daTS in planting out young trees. Thus during the last summer some thousand acres have beeu planted in a single parish alone Of lat< years private .ndmuWs, too, h ve don-' a great deal to retrieve the tieformation which has bfen going on by planting new trees. In one single parish in Norwar for instance, a proprietor has planted on was'te land no less than a quarter of a million of spruce, fir, and larch trees, all from the Government nurouriea. Ihe price of the voung plant* is one farthing, and only ten percent of the plants die. After thirty years each is valued at 7d in the ground. Tiicse are, of course, valuations in a couutry where both labour and timber are cheap.

SAIL SKATING. When the ports of the Bultic are closed by ice during winter, the pilots and sailors of Arrat'cr Isle at Copenhagen, delight to occupy their leisure houri with the exercise of sk .ting by This sport requires much skill and quite a long apprenticeship, but after a person las become dexterous at it, it offers a very p"-u!iar charm, and when a swift wind causes l.itn to glide along the surface of the ice, he feels himself lifted, as it were, and experi, nces n fensation analagous to that of flight. The sail, which is formed of a light, but strong fab-i'-, is stre'ehed over a bamboo fratre. The centre cros*piece, which must he placed at the level of the shoulder*, j s fastened to the skater's body by bands that rnM«s the breast and afterwi rds pas* around t l i!< waist, so tint they may tie inffontr ontont 0 nt Large cr >-epieres of wood, attache 1 to the ower eorners of the system, are h-ld in the skater's hand*, so that he may trim the rail in one d rtctiou cr another. When the eka'er wi-hes to be carried along by the wind, he must stand Tery erect, without stiffening his bolv too inuih, and bend b ck in proportion as the wind blows fresher. Confidence jg acquired by practice. I'.y inclining the sail in one direction or another, tho skater may tack to the larboard or starboard Finally, when it is desired to move against the wind, by skath g in the usual way, the body is bent forward in such a way t hat the sail lies horizontally, and no longer offers a purchase to tho oeri d current. The skater can thus re'urn to his starting point, and from thencbe dliven forward again by tho wind. This exercise is a very agreeable one, and not very dangerous ; and the falls that a person gets in btgiuning aro not much to be dreaded, because they almost always occur backwards The degree of speed that can be attained by a practiced skater is considerable, and yet is less than that of certain iceboats when these are sailing in high winds When the skater gets through using his apparatus, be detaches it from his shoulder', winds the sails around Ihe bamboo sticks, which may be separated from them, and thus hts an object that is no more trouble to carry than an umbrella would