1873O Miveralogy. 415 



At the same meeting of the Iron and Steel Institute, Mr. T. R. Crampton 

 read a paper on the " Combustion of Powdered Fuel in Revolving Furnaces, 

 and its application to Heating and Puddling Furnaces." 



The conditions under which highly silicated pig-iron is produced in the 

 blast-furnace have been studied by M. Samson Jordan, who has lately com- 

 municated the results of his researches to the French Academy of Sciences. 

 His observations were made at the Heerdt Iron-works, near Dusseldorf. He 

 concludes that the furnace should be worked slowly at a high temperature, 

 and that the charge should be rich in silica and alumina. 



Although scheme after scheme has been proposed for the utilisation of 

 blast-furnace slags, which are so terrible a burden to the ironmaster, it cannot 

 be said that any of these schemes have hitherto been entirely successful. 

 Mr. Wood, of the Tees Iron-works, at Middlesbro', has, however, recently 

 invented a machine for crushing blast-furnace slag, until it is reduced to the 

 consistency of sand. Mixed with 8 or 10 per cent of quicklime, this sand 

 when compressed is said to make excellent concrete bricks, which can be used 

 for building without requiring to be burnt. Moreover, it is suggested that the 

 slag-sand may be advantageously used as a manure. 



Bricks of slag are also now made by Mr. Woodward, of Darlington. He 

 merely runs the cinder from the furnaces into moulds, and then subjects the 

 bricks to a process of annealing. 



It is worth recording that the fusion of platinum in a furnace of powerful 

 draught has been effected by M. Violette. Fifty grammes of platinum, partly 

 in fragments and partly in the state of sponge, were placed in a Hessian 

 crucible lined with plumbago, and subjected for one hour to the heat of the 

 furnace. A perfectly-fused button of platinum, of the same weight as that of 

 the metal introduced, was found at the bottom of the crucible. 



In consequence of the great advance in the price of nickel, a correspondent 

 of " The Times," pretty generally known to be Dr. Percy, has called attention 

 to the fact that a substitute for nickel-silver has long been known, though not 

 manufactured. By substituting manganese for nickel, the writer found that 

 an alloy might be obtained, having all the characters of German silver ; but 

 though this alloy was known more than twenty years ago its manufacture has 

 hitherto, for commercial reasons, been suppressed. The present price of 

 nickel — consequent upon the great demand for this metal for purposes of 

 coinage, as well as for nickel-silver and for electro nickel-plating — may lead 

 to the manufacture of this manganese alloy in the place of ordinary German 

 silver. 



As the contemplated reform in the German coinage is expected to absorb an 

 enormous quantity of nickel within the next two years, it is worth noting that 

 some authorities have suggested that other metals, instead of nickel-alloys, 

 might advantageously be used for the new coins. Dr. Clemens Winkler 

 strongly advocates the employment of pure aluminium for small pieces, and 

 points to the properties of this metal as precisely those which adapt it in an 

 eminent degree for the purposes of coinage. 



MINERALOGY, 



Every student of mineralogy is familiar with the fine icositetrahedral, or 

 24-faced, crystals of Leucite, which occur embedded in the lavas of Vesuvius, 

 and were formerly called " white garnets." These crystals are always 

 regarded as characteristic forms of the cubic system — so characteristic, indeed, 

 that the icositetrahedron has been called, in Haidinger's nomenclature, the 

 Lencitoid. Prof. Vom Rath, of Bonn, has, however, been led to study these 

 crystals in a new light, and the results of this study show that the mineral 

 must be transferred from the cubic to the pyramidal system.* By observing 

 the direction of certain striae on the trapezoidal faces of some of these crystals, 

 he found that they were not mere superficial markings, but were really the 



* Leonharlt and Geinitz's " Neues Jahrbuch fur Mineralogie, U.S.W.," 1873, Heft II., 

 page 113. 



