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Census of the fluorspar industry
236
Notes a~zd Comments.
[J. F. I,
copper ean, however, be used, the choice depending of eourse upon t h e nature of the article for which it is intended. The copper or alloy is usually put into t h e required shape (e. g., a wheel or tool) before tempering. T h e castings are t h e n heated for a suitable time, say three minutes, over a fire, preferably a ehareoal fire, at the proper temperature. T h e best results are obtained w h e n t h e t e m p e r a t u r e is raised to t h e m e l t i n g p o i n t of tin. T h e articles are placed on t h e fire and, t o g e t h e r with t h e n e i g h b o r i n g blocks of charcoal, sprinkled with powdered sulphur, till they are entirely covered by it, t h e sulphur-vapor thus being b r o u g h t into contact with the castings. I t is best to add the sulp h u r w h e n the artieles are t h o r o u g h l y heated. After being covered with t h e sulphur the castings r e m a i n in the fire for a time; they are t h e n p l u n g e d hot into a solution of blue vitriol, a n d allowed to r e m a i n in;it for a short period. W h e n the castings are t a k e n from t h e vitriol, it is well to reheat them, and allow t h e m to cool without t h e i n t e r v e n t i o n of a cooling mixture. The new m e t h o d of treating copper a n d its various alloys produces a r e m a r k a b l e hardness without i m p a i r i n g t h e ductility of t h e metal, t h u s rendering it specially useful for purposes for w h i c h a h i g h degree of hardness and, at t h e same time malleability, ductility and toughness are required.--Scientiflc American Sup-
~lement. E L E C T R O L Y T I C M E T H O D OF E S T I M A T I N G GOLD. At a recent m e e t i n g of t h e Faraday Society, Dr. F. M. Perkins a n d Mr. XV. C. Prebble gave the results of researehes to arrive at a n electrolytic m e t h o d of estimating gold which should be perfectly accurate, a n d yet far more rapid t h a n t h e ordinary double cyanide m e t h o d w h i c h the authors, differing from Classen, consider inordinately long, even in hot solutions. Solutions of sodium thiosulphate, cyanide, sodium sulphide, potassium t h i o c y a n a t e and a m m o n i u m t h i o c y a n a t e were all tried and t h e results eompared. T h e firstn a m e d was useless; of the o t h e r s - - w h i e h are all a c c u r a t e - - t h e thiocyanates gave the best results a n d t h e a m m o n i u m salt was better t h a n the potassium. W i t h currents of 0"2 ampere per square decimeter, t h e deposition of o'05 to o'o8 gram of gold was complete in five or six hours. W i t h a current of 0"4 to o'5 ampere, I'5 to 2 hours suffieed. T h e presence of a little persulphate considerably reduced t h e voltage required. E x p e r i m e n t s were also made to d e t e r m i n e the best m e t h o d of removing the deposited gold. Chlorine or bromine water was satisfactory, b u t slow; aqua regia was risky; the authors r e c o m m e n d e d a 2 per eent. solution of potassium cyanide c o n t a i n i n g a little h y d r o g e n peroxide or a persulphate. One or two minutes t h e n suffieed to remove t h e gold.--Scientiflc American. C E N S U S OF T H E F L U O R S P A R I N D U S T R Y . The m i n i n g of fluorspar has increased over 5o0 per cent. d u r i n g the past decade, owing to the greater use of this m i n e r a l in metallurgieal proeesses, especially in t h e iron industry, according to a special report compiled for the Twelfth Census, soon to be published. T h e first statistics of production were collected at t h e E l e v e n t h Census, and these are eompared with t h e statistics for 19o2 in the following" table :
Sept., I9o4.]
Notes and Comments.
237
~902. x889. Quantity, short tons . . . . . . . . . . . . . 48,818 9,50o Value . . . . . . . . . . . . . . . . . . "~275,682 $45,855 Of t h e twenty-two mines in i9o2 , fourteen were in K e n t u c k y , five in Illinois, two in Arizona and one in Tennessee. In these twelve years Illinois, which was the only State producing fluorspar commercially in ~889, has increased its production from 9,5co to I8;86o tons. In the fluorspar deposits of Illinois and K e n t u c k y t h e r e ' is k n o w n to be a very large supply of this mineral, capable of meeting the d e m a n d for m a n y years. As this overcomes one of the objections often advanced against using fluorspar in the smelting of iron--namely, that a constant supply of this mineral could not be depended u p o n - - i t s use for this purpose should now increase rapidly. Thus far the larger proportion of t h e fluorspar mined has been used in steel works. Very little is used in blast furnaces or in the smelting of copper or other metals; for these purposes, and also in foundry work, its use will undoubtedly increase rapidly when its value as a flux is more thoroughly , understood. The average value per ton has varied from $~ to ~ . The average was exceptionally high in the years I896 to x898 , inclusive, reaching $8.2t in I898. In t9o2 it was $5.66 ; the prices reported for that year varied from $2.86 to $tI.5o per ton, this h i g h e r value being obtained for the fluorspar m i n e d in Arizona, which was used in Califoruia.--Iron Age. PROCESS FOR H A R D E N I N G IRON. A new process for hardening iron has been developed by two Prussian inventors, according to the Engineer. It consists in adding to iron a small percentage of phosphorus combined with a large amount of carbon. The iron is heated in a tempering powder consisting of bone dust, to which are added 300 grains of yellow prussiate, 25o grains of cyanide of potassium and 40o grains of phosphorus. The receptacle is closed and luted with clay, and raised to a clear red or white heat. The material treated is t h e n taken out and plunged, while still hot, into a warm bath. It is claimed that this will harden the surface of a piece of iron w e i g h i n g 400 pounds to a d e p t h of about 0"04 inch, and that the iron can neither be cut nor chipped by the best steel used, and that it can be readily welded. A C H A N G E IN BRITISH PATENT LAWS. A radical change in the granting of patents will go into effect in Great Britain on the first day of next year. The British patent laws as they now stand have been very unsatisfactory to both inventors and the public, because a patent has always been granted at t h e risk of the applicant, without any efficient Search b e i n g made into the originality of the alleged invention. Complaint was made that patents which had absolutely no right to exist were too frequently used for the purpose of levying blackmail on manufacturers and others interested in goods manufactured under patents which were valid. The inventor has been given no warning whatever that his supposed invention was in reality no invention at all. Naturally a patent had much less value
Notes a~zd Comments.
[J. F. I,
copper ean, however, be used, the choice depending of eourse upon t h e nature of the article for which it is intended. The copper or alloy is usually put into t h e required shape (e. g., a wheel or tool) before tempering. T h e castings are t h e n heated for a suitable time, say three minutes, over a fire, preferably a ehareoal fire, at the proper temperature. T h e best results are obtained w h e n t h e t e m p e r a t u r e is raised to t h e m e l t i n g p o i n t of tin. T h e articles are placed on t h e fire and, t o g e t h e r with t h e n e i g h b o r i n g blocks of charcoal, sprinkled with powdered sulphur, till they are entirely covered by it, t h e sulphur-vapor thus being b r o u g h t into contact with the castings. I t is best to add the sulp h u r w h e n the artieles are t h o r o u g h l y heated. After being covered with t h e sulphur the castings r e m a i n in the fire for a time; they are t h e n p l u n g e d hot into a solution of blue vitriol, a n d allowed to r e m a i n in;it for a short period. W h e n the castings are t a k e n from t h e vitriol, it is well to reheat them, and allow t h e m to cool without t h e i n t e r v e n t i o n of a cooling mixture. The new m e t h o d of treating copper a n d its various alloys produces a r e m a r k a b l e hardness without i m p a i r i n g t h e ductility of t h e metal, t h u s rendering it specially useful for purposes for w h i c h a h i g h degree of hardness and, at t h e same time malleability, ductility and toughness are required.--Scientiflc American Sup-
~lement. E L E C T R O L Y T I C M E T H O D OF E S T I M A T I N G GOLD. At a recent m e e t i n g of t h e Faraday Society, Dr. F. M. Perkins a n d Mr. XV. C. Prebble gave the results of researehes to arrive at a n electrolytic m e t h o d of estimating gold which should be perfectly accurate, a n d yet far more rapid t h a n t h e ordinary double cyanide m e t h o d w h i c h the authors, differing from Classen, consider inordinately long, even in hot solutions. Solutions of sodium thiosulphate, cyanide, sodium sulphide, potassium t h i o c y a n a t e and a m m o n i u m t h i o c y a n a t e were all tried and t h e results eompared. T h e firstn a m e d was useless; of the o t h e r s - - w h i e h are all a c c u r a t e - - t h e thiocyanates gave the best results a n d t h e a m m o n i u m salt was better t h a n the potassium. W i t h currents of 0"2 ampere per square decimeter, t h e deposition of o'05 to o'o8 gram of gold was complete in five or six hours. W i t h a current of 0"4 to o'5 ampere, I'5 to 2 hours suffieed. T h e presence of a little persulphate considerably reduced t h e voltage required. E x p e r i m e n t s were also made to d e t e r m i n e the best m e t h o d of removing the deposited gold. Chlorine or bromine water was satisfactory, b u t slow; aqua regia was risky; the authors r e c o m m e n d e d a 2 per eent. solution of potassium cyanide c o n t a i n i n g a little h y d r o g e n peroxide or a persulphate. One or two minutes t h e n suffieed to remove t h e gold.--Scientiflc American. C E N S U S OF T H E F L U O R S P A R I N D U S T R Y . The m i n i n g of fluorspar has increased over 5o0 per cent. d u r i n g the past decade, owing to the greater use of this m i n e r a l in metallurgieal proeesses, especially in t h e iron industry, according to a special report compiled for the Twelfth Census, soon to be published. T h e first statistics of production were collected at t h e E l e v e n t h Census, and these are eompared with t h e statistics for 19o2 in the following" table :
Sept., I9o4.]
Notes and Comments.
237
~902. x889. Quantity, short tons . . . . . . . . . . . . . 48,818 9,50o Value . . . . . . . . . . . . . . . . . . "~275,682 $45,855 Of t h e twenty-two mines in i9o2 , fourteen were in K e n t u c k y , five in Illinois, two in Arizona and one in Tennessee. In these twelve years Illinois, which was the only State producing fluorspar commercially in ~889, has increased its production from 9,5co to I8;86o tons. In the fluorspar deposits of Illinois and K e n t u c k y t h e r e ' is k n o w n to be a very large supply of this mineral, capable of meeting the d e m a n d for m a n y years. As this overcomes one of the objections often advanced against using fluorspar in the smelting of iron--namely, that a constant supply of this mineral could not be depended u p o n - - i t s use for this purpose should now increase rapidly. Thus far the larger proportion of t h e fluorspar mined has been used in steel works. Very little is used in blast furnaces or in the smelting of copper or other metals; for these purposes, and also in foundry work, its use will undoubtedly increase rapidly when its value as a flux is more thoroughly , understood. The average value per ton has varied from $~ to ~ . The average was exceptionally high in the years I896 to x898 , inclusive, reaching $8.2t in I898. In t9o2 it was $5.66 ; the prices reported for that year varied from $2.86 to $tI.5o per ton, this h i g h e r value being obtained for the fluorspar m i n e d in Arizona, which was used in Califoruia.--Iron Age. PROCESS FOR H A R D E N I N G IRON. A new process for hardening iron has been developed by two Prussian inventors, according to the Engineer. It consists in adding to iron a small percentage of phosphorus combined with a large amount of carbon. The iron is heated in a tempering powder consisting of bone dust, to which are added 300 grains of yellow prussiate, 25o grains of cyanide of potassium and 40o grains of phosphorus. The receptacle is closed and luted with clay, and raised to a clear red or white heat. The material treated is t h e n taken out and plunged, while still hot, into a warm bath. It is claimed that this will harden the surface of a piece of iron w e i g h i n g 400 pounds to a d e p t h of about 0"04 inch, and that the iron can neither be cut nor chipped by the best steel used, and that it can be readily welded. A C H A N G E IN BRITISH PATENT LAWS. A radical change in the granting of patents will go into effect in Great Britain on the first day of next year. The British patent laws as they now stand have been very unsatisfactory to both inventors and the public, because a patent has always been granted at t h e risk of the applicant, without any efficient Search b e i n g made into the originality of the alleged invention. Complaint was made that patents which had absolutely no right to exist were too frequently used for the purpose of levying blackmail on manufacturers and others interested in goods manufactured under patents which were valid. The inventor has been given no warning whatever that his supposed invention was in reality no invention at all. Naturally a patent had much less value