SCIENCE NOTES.

Otago Witness, Issue 3244, 17 May 1916, Page 73

SCIENCE NOTES.

A Strirv Stacker.- _ A machine that does away with the laborious process of stacking straw with pitchforks has been put into use on some farms n Kansas, U.S.A. The apparatus performs its task as an elevator, racing the straw from the ground and depositing it on the. ton of the stack. The elevator works on pXys attached to a stiff frame on wheci6 A rope drawn by horses lifts the weight to the desired height, whui a catch.is released by the operator, and the platform fcufc. and the straw slides off. A Caulkiug Compound \ o-ood caulking compound can be mad-: by melting separately lib of beeswax and 2oz of resin. When melted mix them together. This amount is sufficient to caulk a 16ft boat. The compound must be apphei. while hot, and can be poured into the seams or applied with a varnish brush, and the surplus scraped off with a putty knne. The hot compound will perforate the wood, thu-i obtaining perfectly water-tight seams. If the seams are very large first caulk tightly with cotton. An Oil-proof Cement.— A cement which will not bo affected by oil is made by mixing glycerine and litharge tn the consistency cf a thick paste. This ■will be found very handy m repairing cracked oil reservoirs, or in making an oil-tight joint between two metal plat?s. The cement should be applied as soon as it is mixed, since it hardens very quickly. Protective Stripes Used by Savages.— Describing in the Geographical Journal his explorations in the Belgian Congo, Dr Cuthbert Christy records that in travelling from Stanleyville to Avakubi he came upon a group of forest natives remarkable foi the curious way in which they mark their bodies for the purpose of concealment. Narrow stripes of black or red are marked on limbs and face, and sometimes the body. This device has the effect of breaking up the outline and making the person less conspicuous in the lights and of the imderwood. Even in the sunlight the duikerboks of the forest will run paflt the motionless hunter without perceiving him, and are caught in the nets. It is interesting to note that an analogous device has. come into use during the present European war for concealing vessels, guns, etc. Riveting Without Rivets.— Electric current, reduced to an extremely low voltage, but increased in volume to tremendous proportions by the use of huge transformers, finds an unusual and spectacular application in performing the work that rivets are intended to perform. The chief distinction between the ordinary rivet and the electric rivet is the difference in time that is required in the two operations. The results are equally successful. Electrical riveting requires much less time. Rivetting, however, is not the precise word, as •welding is the operation that actually takes place. Two layers of metal to bo joined are placed together between the jaws of the giant machine. A lover is pulled, electric sparks fly, the spot between the jaws quickly heats to brightness, and the two surfaces melt and flow together. The result is « permanent, but practically unnoticeable, weld. Human Characteristics in Ape 3.. — Mr R. L. Garner, who has devoted the best years of his life to the study of the African anthropoid apes in their native haunts, recently delivered a notable address before the Biological Society of Washington on the habits and social conditions of these animals. In many respects they resemble closely the lower races of humanity. Their diet is mainly vegetable; hut flesh is an essential or it. They sleep on the back or sico, ike human brings, and often make their beds 18ft to 26ft off the ground. They have acuto sight, and e»oec!ally hearing, but their sense of smell L-i

not much better developed than that of man while the sense of touch is less, acute than in man. The period of gelation is probably seven months. Twin births are exceedingly rare. Females are sexually mature at from seven to nine years; males a year or two later. The usual duration of life is 20 to 21 years. Rights of ownership are well respected among them. Prevention of Fog by Oil. — The use of oil as a preventive of fog holds forth much promise, although it would appear that its possibilities have not yet been fully determined in the absence of a series of' exhaustive experiments. It is lamed from the Hydrographic Bulletin that experiments to prevent the fogs in river valleys have been made in Fiance with variable success, the best results being obtained by employing vegetable The procedure is to cover the surface of the water with a thin film of oil, which keeps the air from coming in contact with the warmer water, thus hindering the condensation oi the water-vapour. According to one authority, it is possible for a ship which has to stop or anchor iff a fog-bound coast to create a clear zone around her by distributing storm oil for a time. In calm weather good vegetablo oil can bo used with advantage in clearing a pathway or zone through a fog bank, provided the fog is caused by the evaporation of surface water. With a 'strong wind the effect is lost, except possibly in the direction in which the wind is blowing. The effect of wind, however, may be overcome, it seems, by distributing oil over a considerable portion of the sea. Enclosed waters might be cleared of fog by having several distributing stations for oil and taking advantage of tides in spreading the oil, thus minimising the effect of wind.