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Technical notes
452
Notes aJzd CommeuZs.
[J. F. I.,
RADIO-ACTIVE E L E M E N T S . T h e opening address of Prof. W. N. Hardley, president of the Section of Chemistry, at the last meeting of the British Association-for the Advancement of Science, contains the following interesting reference to the so-called radioactive elements: " From the study of rays of measurable wave-lengths we have lately sailed under the guidance of M. Henri Becquerel into another region where it is doubtful whether all the rays conform to the undulatory theory. In fact some of the rays are believed to be charged particles of matter, charged, that is to say, with electricity. Beyond doubt they are possessed of very extraordinary properties, inaamuch as they are able to penetrate the clothing, celluloid, gutta percha, glass and various metals. They are, moreover, endowed with a no less remarkable physiological action, producing blisters and ulcerations in the flesh which are difficult to heal. It is an established fact that such effects have been caused by only a few centigrams of a radium compound contained in a glass tube enclosed in a thin metallic box carried in the pocket. " From this we can quite understand that there is no exaggeration in the statement attributed to the discoverer, Professor Curie, by Mr. W. J. Hammer, of the American Institute of Electrical Engineers, that he ~-ould not care to trust himself in a room with a kilogram of pure radium, because it would doubtless clestroy his eyesight, burn all the skin off his body, and probably kill h i m . "
T E C H N I C A L NOTES. Although the United States consumed last year approximately 520,537 long tons sulphur, exclusive of the sulphur recovered from the fumes from roasting blende, its own supply was little more than one-quarter of this quantity, chiefly in iron pyrites. The bulk of the demand is still satisfied by imports of brimstone from Sicily, and of iron and copper pyrites from Spain and other countries. Metallic calcium is likely to become an important industrial product, if the methods of manufacture eau be improved so as to reduce the cost. It is of value as a reducing agent and as a purifier of iron. The present cost of manufacture by electrolysis is about 45 cents per pound. The steam turbine, which, m a n y engineers think, promises to revolutionize the generation of power from coal, is, on account of its high speed, especially suited to the driving of electrical dynamos. The General Electric Company was quick to perceive this, in taking up the manufacture of the Curtis turbine engine, which it is now exploiting on a large scale. Platinum is obtained in ordinary placer mining, in the Urals, California and elsewhere, but its occurrence in place in the rock is very rare and difficult of determination. It has been found in the peridotite, serpentine and olivine rocks of the Urals, but so finely disseminated that careful search has but rarely proved successful. As greater d e p t h is attained in Dolcoath mine, Cornwall, the finer becomes the tin; that is to say, the particles of cassiterite become more minute. This necessitates stamping to a greater degree, with additional care in t r e a t m e n t of slimes. With an ore containing only I"5 to I'75 per cent., the treatment is a difficult matter.--Eugincerilt.¢ and Mi.ning./ournal.
Notes aJzd CommeuZs.
[J. F. I.,
RADIO-ACTIVE E L E M E N T S . T h e opening address of Prof. W. N. Hardley, president of the Section of Chemistry, at the last meeting of the British Association-for the Advancement of Science, contains the following interesting reference to the so-called radioactive elements: " From the study of rays of measurable wave-lengths we have lately sailed under the guidance of M. Henri Becquerel into another region where it is doubtful whether all the rays conform to the undulatory theory. In fact some of the rays are believed to be charged particles of matter, charged, that is to say, with electricity. Beyond doubt they are possessed of very extraordinary properties, inaamuch as they are able to penetrate the clothing, celluloid, gutta percha, glass and various metals. They are, moreover, endowed with a no less remarkable physiological action, producing blisters and ulcerations in the flesh which are difficult to heal. It is an established fact that such effects have been caused by only a few centigrams of a radium compound contained in a glass tube enclosed in a thin metallic box carried in the pocket. " From this we can quite understand that there is no exaggeration in the statement attributed to the discoverer, Professor Curie, by Mr. W. J. Hammer, of the American Institute of Electrical Engineers, that he ~-ould not care to trust himself in a room with a kilogram of pure radium, because it would doubtless clestroy his eyesight, burn all the skin off his body, and probably kill h i m . "
T E C H N I C A L NOTES. Although the United States consumed last year approximately 520,537 long tons sulphur, exclusive of the sulphur recovered from the fumes from roasting blende, its own supply was little more than one-quarter of this quantity, chiefly in iron pyrites. The bulk of the demand is still satisfied by imports of brimstone from Sicily, and of iron and copper pyrites from Spain and other countries. Metallic calcium is likely to become an important industrial product, if the methods of manufacture eau be improved so as to reduce the cost. It is of value as a reducing agent and as a purifier of iron. The present cost of manufacture by electrolysis is about 45 cents per pound. The steam turbine, which, m a n y engineers think, promises to revolutionize the generation of power from coal, is, on account of its high speed, especially suited to the driving of electrical dynamos. The General Electric Company was quick to perceive this, in taking up the manufacture of the Curtis turbine engine, which it is now exploiting on a large scale. Platinum is obtained in ordinary placer mining, in the Urals, California and elsewhere, but its occurrence in place in the rock is very rare and difficult of determination. It has been found in the peridotite, serpentine and olivine rocks of the Urals, but so finely disseminated that careful search has but rarely proved successful. As greater d e p t h is attained in Dolcoath mine, Cornwall, the finer becomes the tin; that is to say, the particles of cassiterite become more minute. This necessitates stamping to a greater degree, with additional care in t r e a t m e n t of slimes. With an ore containing only I"5 to I'75 per cent., the treatment is a difficult matter.--Eugincerilt.¢ and Mi.ning./ournal.