Science Siftings

New Zealand Tablet, 14 August 1913, Page 49

Science Siftings

By 'Volt.'

;"■:... First Condensed Milk. The idea of condensing milk to make it.. keep better occurred first to a French chemist named Appert, in 1827. Seven years later the method of evaporating the milk in rarified air to prevent it from reaching the boiling point was first used. Commercially .the process was first exploited, in the United States, where there are at present about 50 factories which dispose of 200,000,000 pounds of condensed milk a year, valued at about -£2,500,000. s Ancient Incubators. Few people who wrestle with the chicken incubator problem, and often fail to solve it satisfactorily, realise what an old art it is and how it was brought to a high state of perfection thousands of years ago by ancient Chinese and Egyptians. It was an hereditary profession with both nations, and its secrets guarded with a zeal which was almost religious and handed down from father to son., The men who manipulated the incubators were held in the greatest reverence and respect. Even before the French Revolution the Paris markets had incubator chickens, thanks to the Bonnemain process, which was invented in 1779. How Diamonds Originated. Recent scientific authorities are inclining to the belief that all diamonds came to the earth, in meteoric showers. The theory is the diamond fell to the earth as a meteorite at a late period of the earth's formation. Localities where diamonds are found contain meteoric masses which have penetrated the earth more or less deeply. Late discoveries in Arizona seem to indicate further the ' heavenly origin' of our most brilliant stone, for over the broad and open plains for areas of miles in diameter several thousand masses of metallic iron have been scattered. These masses have undoubtedly been meteoric showers. Not long ago an enthusiastic mineralogist, working on the mass, cut into a section and found that the tools were injured by something harder than metallic iron. He examined the specimens chemically and soon announced that the meteorite contained black and transparent diamonds. And since then the search for diamonds in meteorites has occupied the attention of chemists all over the world. Again, it is claimed that it is possible that the so-called ' volcanic pipes' at the Kimberley diamond mines and elsewhere are not volcanic, but ' simply holes bored in the solid earth by the monstrous meteors, the larger masses boring the holes, while the smaller masses, disintegrating in their fall, distributed diamonds broadcast.' Latent Pressure in Rock Strata. Although all underground boring such as mine galleries are subjected, to the effects of the weights of overlying strata as a natural consequence, it appears to be found that the effects which are noticed in such cases are not entirely due to the weight of the soil, so' that other causes must be supposed, especially the action of the latent pressure coming from earth movements which may have been maintained clear up to the present time. The French scientist, Lapparent, was led to think that all the rock strata of the globe are more or less compressed from mechanical movements which they underwent in the course of ages. Chief Engineer Morin, of the Levin mines in France, made some observations on this subject. While mine tunnels were being put through, or shortly after, he noticed slow movements of the ground, which cannot always be accounted for by the simple weight of overlying earth. Certain places showed an abnormal pressure at various levels underground, and at other points he found very great pressures at small depths, and on the contrary low pressures at great depths. "Considering 'various observations, he is led to believe in a latent pressure in rock strata.