SCIENCE NOTES.

Otago Witness, Issue 2286, 23 December 1897, Page 54

SCIENCE NOTES.

• . • Much has been said and written about improved machinery and its tendency to displace labour, but had it not been available for copper mining it is believed the true wealth of some mines would never be known, and the Tamarack mine and famous Red Jacket shaft of the Calumet and Heel a would probably never have been put down. The sinking of shafts to a depth of a mile has been made practicable by the use of drilling machines and high explosives*. To sink a shaft similar to those above mentioned by hammer- and drill would be almost impossible. With hand labour not more than 25fc a month could be sunk, at which rate it would take about 16 years to sink the Tamarack No. 5, and it i 8 unlikely that the project would have been undertaken under such conditions. So that while the drilling machine has displaced a number of men, it has been the means of developing properties wbich otherwise would likely be left untouched, thereby giving employment to more men than could have fouad work in the. mines had the old Bystem b£ mioing by hand labour been continued.

• . • A tablespoonf ul of liquid air poured on about, a fluid ounce of whisky will freeze it at once into flat scales, giving the whole the appearance and -colour of cyanide of potassium. This may be emptied out on a table, and will remain frozen in that condition for folly five minutes. One thing that impresses one is that while all molecular motion is practically arrested at this temperature, the odour is psrfectly distinct, showing that the3e particles which stimulate the sense of smell are active and independent of the temperature. A handkerchief of either silk, linen, or cotton saturated with the liquid will b8 charred and destroyed jost the same as if it were put in an oven and browned, though no change of colour is apparent. Its evaporation is quite slow, and it may be carried about for a number of hours in an open vessel without entirely disappearing. It probably represents a, compression of about 700 atmospheres, and "would therefore, in a confined epaca and at 60deg temperatnre, represent a pressure of somewhere from 10,0001b to 12,0001b to the square inch.

• . • A short lime ago attention was drawn to the fact that some of the common varieties of the beautiful and popular primula produce eruptions of an erypipelas-like character- when handled by people with lender skin?. Gardeners well know that similar forms of skin disease are sometimes produced in persona handling and cleaning the bulbs of the common hyacinth. The cause of thiß inflammation was revealed by De Morris, of the Eoyal Gardens, Kew, at a recent meeting of the Linnean Society. There was n© doubt about the reality of the effect, for scales from the bulbs were found to be capable of producing considerable irritation in certain cases when placed upon the skin. The prime agents of the injuries are minute aeedle-shatied crystals of cxalate of

lime arranged in close bundles on the bulb scales. The crystals seem to act as prote'e tors of the growing plants, for snails avoid hyacinth bulbs while other bulbs close by are attacked. Roman hyacinths appear to produce more serious skin disorders, than other varieties. Dr D. H. Scott has confirmed the conclusion that the irritation of the, skin produced by handling hyacinth bulbs is really due to punctures by the minute crystals observed by Dr Morris.

* . ' The invention of an improved kind of diving bell is reported from Paris. It consists of a steel-plated bowl or globs about 10ft in diameter, and weighing as many tone, wbich can be propelled along a river bottom by the agency of electricity. For the admission of the crew, consisting of from four to six persons, a manhole is provided, and the cabin contains sufficient air— so it is said — to last them 48 hours 1 The orew can communicate with a boat, or with the adjacent land, by telephone, and when they wish to ascend they simply overturn two tanks filled with ballast. This wonderful machine has recently been employed in exploring the bed of the Seine, and its inventor has sanguine hopes that it will do remarkable things in deep-sea work, the discovery of tb'e exicfc whereabouts of the ill-fated Drummond Castle being mentioned as one of the possibilities in store, for it. It will also be useful in repairing cables, and in the pearl and sponge fisheries. There appears to be no pump or air supply to this new-fangled diving bell, and unless the inventor has learnt how to override the laws of Nature, he will find that at a certain depth his strange vessel will become half-full of water. In the old-fashioned diving bell the function of the air tube is to keep the water out, besides furnishing fresh oxygen for the inmates. '

• . • The lightest balloon that has ever been built for continual use weighs a little over" 601b complete. -Of. this 91b is the weight of the netting ,and Tib that of the basket. This, balloon is built to hold 4000 ft oE hydrogen gas on the , estimate that 1000 ft of gas will lift 601b, although theoretically it will lift 70lb.

• . • Sir John Evens, the new president of the British Association, has attacked our paleolithic pretensions (says the Scientific American). For years it has been thought that the State of Ntw Jersey was at one time inhabited by men who were the contemporaries of the post-glacial men of Europe. Sir John Evans, the highest living authority on the antiquity of man, tella us the chipped stone implements fonnd in the Trenton gravels are not paleolithic at all, but were probably made by the red Indians. Such words, coming from so eminent an anthropologist, will njobably cause a reexamination of the Trenton implements now that the axe of scientific doubt has assailed the family line ascendant of the original inhabitants of America. Chipped flint weapon?, which showed no signs of grinding and polishing, totally unlike those found at the surface, have been discovered at the bottom'of thick beds of gravel in the valley of the Somixie at Amiens and Abbeville. From the nature of the evidence these implements showed the handiwork of man who existed after the glacial pericd. On the floor of ewes chipped stone weapons were found which had been overlaid by a thick layer of stalagmite, which forms with extreme slowness. On the top of the stalagmite neolithic or polished atone weapons were also found. Now between the handiwork of these two races of man ages most have passed sufficient for an entire change of climate and fauna. " Ib was at this point of the discourse that Sir John impugned the authenticity of our glacial pedigree. He declared his firm conviction that the American relics were neolithic, and therefore of far less antiquity than the rudely-fashioned relics found in the valleys of the Seine and the Somme. If the American relics could be shown to have been the work of people existing shortly after the glacial period, it is plain from their superior workmanship that the paleontological man in America most have possessed greater intelligence than the man of the Somme Valley. What militates against this view of the paleolithic man in America is that implements of a similar type to those of the Trenton drift have bees found in some of the disused quarries in which the red Indians fabricated their weapons. Our own men of science have long believed that they saw in these stone implements the work of men who inhabited this continent just after the glacial period. If after a critical examination of tfre whole question it is decided that the weapons are paleolithic and not neolithic, we can only conclude that the development of intelligence was more rapid on the western shores of the Atlantic than en the eastern, and there is little fear that our native paleoliths will lack defenders.

. * , *It is now the rale to disinfect a room in which a case of infections disease has been treated by sulphur fames, while at the same time the pap^r is stripped from the walls. Professor Konig, of Gottingen, advocates the use of mercurial vapour for the same purpose, and says that this mode of treatment is equally efficacious in ridding an apartment of noxious insects. The method of operation is simple, and consists in putting about 2oz of corrosive sublimate (mercuric bichloride) into a plate over a chafing dish, after Healing up with paper the doors and windows of the room. After the expiration of three or four hours the windows are opened and the room thoroughly aired, the person entrusted with

this duty holding a sponge over mouth and nose, and taking care not to inhale tho I vapour of the mercury. * . * Natural as distinguished from artifi* cial and mechanical ventilation consists in providing an opening in or near the ceiling for the outlet of foul air, and an opening at a lower level for the inlet of freßh air. The efficiency of this plan is proved scientifically, eaya the Baildfng World, and is based upon the fact that heat expands and cold contracts. To this natural law air is no exception. Foul air is generally warmed to some extent, and then rise* to and passes out by the opening at the higher level, its place being taken 'by cooler air entering at the lower of the two openings. —Let it be noted here that, in order to ventilate, there must be two openings at the least — one to ace as an inlet, the other as an outlet. The effectiveness of this natural ventilation depends entirely on the difference of temperature be■tween the external air and the internal air, and it will at once be apparent that this system may be very effective in winter and fail absolutely in summer. Air dilates or expands 1491 of its volume for each degree of Fahrenheit that its temperature is raised. Consequently its weight' is reduced in the same proportion, and the lighter air is thus forced to,the upper part of the room' by'fche greater weight of the cooler air— just in' the same way that a bladder of air, submerged in a pond, will be forced to the top by the greater weight of the surrounding water immediately the restraining force is removed. If an opening is made in the upper part oE a {room, the warmer or lighter air passes through, forced through by cooler and heavier air coming into the room through openings at a lower level. As the fresh air is in its turn heated, the' movement is kept up in a constant stream, cold air entering by one set of orifices and hot air escaping by another.