488 



METALS. 



chloric acid, and then thick strips of zinc are 

 placed in the mixture. A lively effervescence 

 ensues, hydrogen is evolved in large quanti- 

 ties, and a porous slimy mass is left, which, on 

 being violently shaken, separates into a fine 

 powder. This must be well washed with hot 

 water, and afterward with alcohol, and a pow- 

 der is then obtained quite free from oxide of 

 copper. Bottger obtains copper powder by 

 reducing the black oxide in a stream of coal- 

 gas. The oxide is placed in a flask, heated 

 strongly over a Bunsen's burner, and then a 

 stream of coal-gas is sent through the flask, by 

 means of two tubes which pass through the 

 cork. The reduction is effected in a few min- 

 utes. Powder obtained by either of these pro- 

 cesses can be employed to form with mercury 

 a soft amalgam, which hardens quickly, and is 

 suitable for the reproduction and multiplication 

 of etched and engraved steel plates. 



Aluminium Bronze and Soldering. M. 

 Hulot, director of the workshops of the manu- 

 factory of postage-stamps, at the Paris Imperial 

 Mint, made a report to the French Academy of 

 Sciences, in June, on some valuable properties of 

 aluminium. He says : "The paper, and especially 

 that gummed and dried, as used for postage- 

 stamps, rapidly deteriorates tools even of the 

 best-tempered steel. The 300 perforators for 

 piercing the postage-stamps are used up after a 

 day's work ; in a few hours their ends become 

 blunted, and instead of piercing, only crush the 

 paper, the last holes made being considerably 

 enlarged. He replaces the steel by aluminium 

 bronze at 10 per cent., and the new tool, 

 striking 126,000 blows per day, has worked, 

 for several months without need of repairs. 

 Aluminium bronze does not unite freely 

 with solder by the old process ; but if we 

 take equal quantities of zinc amalgam and 

 common solder, aluminium bronze can be ad- 

 mirably soldered together by it. This solder 

 becomes better, again, if it is alloyed with once 

 or twice its weight of tin. Thus we have three 

 excellent solders : 1st, solder with half its 

 weight of amalgam; 2d, with a fourth; 3d, 

 with an eighth. This is an excellent discovery, 

 as it places aluminium on a new footing as re- 

 gards mechanical appliances, especially for 

 bushes or bearings for machinery, as the metal 

 is almost indestructible by friction." 



Work* in Bronzed Cast Iron. The Society 

 of Arts Journal describes the method of work- 

 ing bronzed cast iron adopted by the Tucker 

 Manufacturing Company of Boston. The mate- 

 rial employed is American iron of several varie- 

 ties, compounded together with a compai'atively 

 small admixture of the Scottish Coultness iron. 

 A combination, of several important qualities is 

 thus obtained, and a material is produced pos- 

 sessing smoothness in working, softness, and a 

 sufficient degree of strength. The castings 

 having been executed in clean sand, undergo 

 the customary process of pickling in dilute 

 sulphuric acid, after which they are finished 

 on their salient points with the lathe or the 



emery-wheel. The beautiful granulated velvet- 

 like surface of the mat or field, upon which the 

 polished portions of every design appear to 

 rest, is produced by the action of acid, and 

 without the application of any kind of tool. 

 The bronzing, which is the final stage of the 

 manufacture, is accomplished by covering the 

 iron with a film of vegetable oil, and then ex- 

 posing it to heat of a high temperature, by which 

 the desired color is obtained, through the union 

 of the carbonized oil with the oxidized metal. 

 This, therefore, is a permanent bronze, being 

 actually incorporated with the substance of the 

 iron. In some degree the bronze surface pro- 

 duced by this method resembles that of certain 

 steel pens which have a bronze-like aspect, but 

 they are not really alike, for, in the case of the 

 steel pens, the bronze effect is produced by a 

 superficial varnish, which may be removed by 

 the application of alcohol. Lamps, clock-cases, 

 and all works which are usually coated with 

 lacquer or varnish, are now made in bronzed 

 cast iron. 



Soldering Iron and Steel. An improved 

 composition for welding and soldering iron or 

 steel has been patented in Europe by M. Lietar. 

 It consists of 1,000 parts filings of iron or steel, 

 according to whether the composition is in- 

 tended to weld or solder iron or steel ; 500 parts 

 boi'ax ; 50 parts balsam of copaiva or other 

 resinous oil ; and 75 parts ammoniacal salts 

 (hydrochlorate, carbonate, or other). After 

 being thoroughly mixed, the compound is cal- 

 cined and reduced to powder. A portion of it 

 is placed between the two pieces of iron or 

 steel, which require treatment, at the spot 

 where they are to be united ; a cherry-red heat 

 is then applied, at which temperature the sol- 

 dering preparation fuses after which the 

 pieces are withdrawn and the welding opera- 

 tion proceeds in the usual way. If the dimen- 

 sions or shape of the pieces prevents their be- 

 ing subjected to the fire together, they may 

 be welded as follows: Heat first one of the 

 pieces to a cherry-red temperature, at the place 

 where the soldering or welding is to be done ; 

 then put on the composition, and apply the 

 second piece (which has previously been heated 

 to a white heat), then weld the whole to- 

 gether. 



Refining Pig or Cast Iron. Mr. George 

 Crawshaw, of Gateshead-on-Tyne, has intro- 

 duced an improved process of refining pig or 

 cast iron, so that it may be fit for puddling into 

 wrought or malleable iron. His flux is clay 

 and iron slag in proportion to the ton of iron, 

 of four cwt. of clay and six cwt. of slag or mill- 

 cinders. Car^ must be taken that the clay 

 used is as free as possible from sulphur, phos- 

 phorus, and silica. If the flux is not fluid 

 enough, he adds a small .quantity of wrought 

 iron. A small portion of lime, limestone, or 

 chalk, is also found to improve the flux. The 

 clay may be raw or burnt, such as old bricks, 

 if not too sandy. For the purpose of strength- 

 ening and otherwise improving the iron, a 



