May 2nd, 1887." 



SCIENTIFIC NEWS. 



63 



space being 5 feet long by i foot wide and i foot deep. 

 This is closed by a cast-iron slab or cover, having holes, a, a, 

 for the escape of the gases liberated during the operation. 

 At the ends of the furnace arc holes which admit enormous 

 electric light carbons, r, c, about 30 inches long. The 

 operation of producing aluminium-bronze is as follows : — 

 The furnace is nearly filled with finely pulverised charcoal 

 that has been soaked in a solution of lime and water, and 

 then thoroughly dried. A space, s, as shown in Fig. 2, is 

 left in the middle of the furnace. This space is filled with 

 about 18 parts of granulated copper and 14 parts of broken 

 corundum, and some coarsely-broken charcoal. It will be 

 seen by Fig. 2 that the carbon rods or electrodes, c, c, pro- 

 ject into this inner portion of the surface. The whole is 

 then covered with broken charcoal and the lid is put on. 

 The dynamo-machine is connected to the furnace thus pre- 

 pared, by thick copper cables joined to the carbon rods ; and 

 the current is caused to pass through the loosely arranged 

 " charge," fusing the ordinarily almost infusible corundum 



the bronze which had been heated for the purpose of forging. 

 It was allowed to become too hot, and when struck, the 

 entire bar assumed a crystalline condition, some of the indi- 

 vidual crystals being nearly perfect in form. A striking 

 analogy has been observed between them and certain forms 

 of meteorites. Sometimes small fused rubies and sap- 

 phires are discovered amongst the products of the furnace. 

 The suboxide of aluminium — never found in nature, and 

 never before known to exist or to be capable of formation 

 — is always present in larger or smaller quantities. Beauti- 

 ful specimens of white fibrous alumina have also been 

 found. It will thus be evident that very interesting 

 scientific, as well as important economical, results have 

 already been attained by this process, which has been 

 pursued to a successful issue, as far as aluminium bronze is 

 concerned ; and which has also been so far successfully 

 applied to the production of the metal aluminium itself in a 

 comparatively pure state that IVIessrs. Cowles have an- 

 nounced that they expect to be able to put the metal itself 



\N ILKCTRUAL lURNALK, 



like wax, and in a very short time bringing the whole 

 " charge " to a fierce heat by the energy of the current. 

 A suitable means of regulation is employed for keeping the 

 current under control, and the carbons are gradually with- 

 drawn, until they are separated by the whole length of the 

 inner space in which the corundum and copper were placed. 

 At the end of about an hour the operation is completed, 

 the current is switched off, and the furnace is allowed to 

 cool. On being opened an oblong metallic and crystalline 

 mass of white metal is found at the bottom of the furnace. 

 This is the copper charged with from 15 to 35 per cent, of 

 aluminium, obtained from the corundum. It is put into 

 a crucible and run into ingots, which are remelted, and 

 " diluted " with copper in the proper proportion to give a 

 standard bronze containing 10 per cent, of aluminium. 

 Every ingot is tested, and none are allowed to pass unless 

 they show a tensile strength of at least 90,000 lbs. per 

 square inch. 



Besides the aluminium bronze, other substances, and 

 some of them very curious and interesting, are found in 

 the furnace. A remarkable effect was observed in a bar of 



on the market in less than a year, at a price considerably 

 lower than has hitherto been demanded for it. 



We are informed that the Cowles Company, of America, 

 have ordered additional Brush dynamos, of the type 

 shown in our illustration above ; and that for a foundry 

 which has been established in England, Messrs. Crompton 

 and Co. are constructing a dynamo of still larger dimensions 

 and power. It will be evident that any success this pro- 

 cess, or any allied one, may obtain, is due, to a great extent, 

 to the modern dynamo-machine, the improvements effected 

 in which have for the first time rendered it possible to em- 

 ploy the great heating effect of the electric current for 

 metallurgical operations. That this may be done on a 

 large scale will be understood from the fact I hat the Brush 

 dynamo shown above, which is now being used by the Messrs. 

 Cowles, is capable of continuously yielding heat-energy in 

 the electric furnace equivalent to 11,320,000 foot-pounds of 

 work per minute, or more than 340 horse-power. Dynamos of 

 still greater power may readily be designed and constructed 

 if required. The success obtained by the aid of the thirty 

 horse-power Brush machines, which Messrs. Cowles first 



