SCIENTIFIC AND USEFUL

New Zealand Graphic, Volume VIII, Issue 49, 5 December 1891, Page 647

SCIENTIFIC AND USEFUL

THE INDIA-RUBBER TREE. The India-rubber tree cannot stand shade, and unless the seedlings are fully exposed to light and well drained, they cannot grow. Owing to this it is found that in the depths of the forest, where light and air are shut out by the dense crowd of trees of many species, natural reproduction takes place by the germination of seeds carried by birds high up in the crowns of other trees, aerial roots descending in process of time to the ground, and developing into a huge hollow cylinder round the foster stem, which is soon killed. The descent of the roots may take years, but once they have taken hold of the ground, the further growth is exceedingly rapid. ORIGIN OF NEBUL.E. What was the original state of things? How had it come about that by the side of ageing worlds we had nebulie in a relatively younger stage ? Had any of them received their birth from dark suns, which had collided into new life, and so belonged to a second or later generation of the heavenly bodies ? During the short historic period there was no record of such an event; still it would seem to be only through the collision of dark suns, of which the number must be increasing, that a temporary rejuvenescence of the heavens was possible, and by such ebbings and flowings of stellar life that the inevitable end to which evolution in its apparently uncompensated progress was carrying us could, even for a little, be delayed. REMEDY FOR SNAKE POISONING. It is said that a remedy for blood poisoning caused by the bites of snakes and rabid dogs has been discovered in Africa, by a Dr. Engels, in the * wild-growing, black, noble palm.’ Five hundred negroes bitten by poisonous snakes were treated with the extract of the noble palm, and four bundled and eighty-seven were curedin five days. Of sixtyseven farmers and negroes bitten by rabid dogs sixty-five were saved, while two died of weakness. The remedy is injected under the skin, and causes a moderate fever not exceeding 35 5 deg. C. On the third day the patient is without fever, swelling and inflammation of the affected part have disappeared, and on the fifth, or, latest, on the seventh day the patient is cured. PLANT MEMORY. Venus’s fly trap is one of the plants which consumes insects. When a fly gets into the cup a leaf closesoil it like a lid, and prevents tbe victim’s egress. There are certain sensitive hairs which the intruder almost inevitably touches, and that is the signal for shutting the trap-door. But the curious thing is that the leaf won’t move till a hair has been touched twice ; so long as only one touch has been received there is no response, but immediately on the second signal being given down the lid goes. Another curious thing is that the plant remembers for a certain space of time that one touch has been given, and then seems to forgetail about it. If the second touch is given within fifteen to thirty seconds the plant knows that it is the second, and closes up ; but if a longer time elapses other two touches must be given before the lid moves. This seems to suggest a memory, though evidently a somewhat short time. Sir William Macgregor, Governor of British New Guinea, in exploring the Fly River, speaks favourably of the natives of the large island of Kiwai, notwithstanding their ill-repute as cannibals. As agriculturists, he considers they deserve great credit; they produce large quantities of vegetable food. The cultivation of the banana receives from them much attention. In a vocabulary of their language which he compiled, there is a list of no fewer than thirty six different varieties of banana ; and from personal experience, he could testify that the distinctions were not fanciful, but indicate real, substantial differences. Some of the varieties, he says, are very good. They also plant and cultivate sagotrees, of which they distinguish twenty-five varieties; of yams they grow twenty kinds, three of which are remarkably good ; and of sweet potatoes ten, two of which are suited for exportation. During the American War, an officer had to send a messenger across an opening where the oullets were flying dangerously. He selected a very brave man and cautioned him as to his peril, telling him to ride for his life on reaching the open field. Tbe officer watched him through his fieldglass, saw him fling himself behind the flank of his horse for safety, and finally saw him drop from the steed as if mortally wounded. A second man was sent safely on the same errand, while the wounded soldier was cared for. He had merely fainted. On coming to, he found the surgeon at work over him, and anxiously inquired as to the precise nature of the wound. He was told by the surgeon that he had been squarely hit and that the injured part could never be made whole again. ‘ But rest easy,’ said the doctor, ‘ for the shock only took effect—in the canteen .” Tbe man had not been injured in the least, but had been deceived by the flowing of the contents of his cherished canteen, which under the circumstances he naturally mistook for his heart’s blood. The soldier is living yet to laugh over his ludicrous mishap. MAKING A THIEF OF ELECTRICITY. Short-weight gold coins are becoming common. From a careful examination of light pieces now being found, it is evident that the thief has been aided by electricity. The service of an ordinary galvanic battery and some cheap acid is all that is necessary to conduct the operation of the electric process. The scheme is similar to that employed in plating with gold by electricity. The coin is placed in the fluid and attached to it are wires from the poles of the battery leading to another piece of metal prepared to receive, in the form of plating, the metal to be removed from the coin. The battery being set in motion, sufficient gold to form a plating is quickly transferred, and as it is removed uniformly from all parts of the coin, the

liability of disfigurement is reduced to a minimum. The only effect is to blur the characters slightly. An authority at the mint has estimated that about 5 per cent's worth of gold can be removed in this way from a gold piece without exciting the suspicion of the casual observer. To the skilled eye of the expert, however, the effect is generally apparent at a glance.