532 



METALLURGY. 



METEOROLOGY. 



titles of ferrous oxide do not prevent the quanti- 

 tative separation. The same author separates 

 copper from lead, cadmium, magnesium, man- 

 ganese, mercury, zinc, etc., the metals being 

 present as sulphates or chlorides, by adding 

 nitroso naphthol dissolved in acetic acid. 



The Meritens process for preventing the oxi- 

 dation of iron consists in placing the object near 

 the anode in a bath of distilled water ^at 80 C, 

 a plate of copper acting as cathode. The elec- 

 trolysis forms a layer of magnetic oxide Fe 3 O4, 

 which preserves the iron against all further oxi- 

 dation. Peroxide of lead can also be used. It 

 gives a black, adhesive deposit by the electroly- 

 sis of an alkaline solution of litharge. In an 

 analogous process, invented by Mr. Haswell, iron 

 or steel is plunged as an anode in a bath con- 

 taining from 0*5 to 5 per cent, of chloride or 

 sulphate of manganese, and from 5 to 20 per 

 cent, of nitrate of ammonia. The bath is elec- 

 trolyzed cold with carbon cathodes. Feeble cur- 

 rents cover the iron with a deposit of peroxide 

 of manganese, which adheres well, and is not 

 subject to further oxidation. 



In Francis J. dames' process for coating sheet- 

 iron plates with lead, the usual cleaning of the 

 plates in an acid bath is followed by a supple- 

 mental one under the galvanic current and a 

 bath in chloride of zinc. The plates are then 

 immersed in melted lead, and sal ammoniac, ar- 

 senic, and phosphate of lead are added. The 

 first ingredient seems to drive out absorbed gases 

 that would form bubbles under the surface of 

 the coating; the arsenic to give the coating a 

 greater degree of hardness ; and the phosphate 

 of lead to increase the fluidity and permit an 

 even distribution of the lead over the plates. 



A favorable report has been made by a com- 

 mittee of the Franklin Institute upon the claim 

 of Aimer Thomas and Luzerne Merket, of North 

 East, Pa., for having invented processes for cast- 

 ing pure copper without alloys, so as to make 

 castings sound and free from blow holes; and 

 for hardening copper (after casting) without de- 

 stroying its fiber or impairing its usefulness for 

 electrical or other purposes. 



A method of extracting waste metals from 

 refuse slag and debris of tin-smelting works, in- 

 vented by J. Shears, of London, consists in re- 

 ducing the ore or slag to a powder, fusing it in 

 that state with any alkali, then dissolving the 

 mass in boiling water. The peroxide of iron, 

 with the nickel and cobalt, fall to the bottom and 

 are separated by decantation. The tin is elimi- 

 nated from the remaining liquid by passing an 

 electric current through anodes immersed in it, 

 and falls to the bottom of the vessel in a fine 

 metallic powder. 



Thomas Fletcher has found the processes of 

 brazing and welding facilitated by the use of 

 compressed oxygen, which can be obtained very 

 cheaply, under Binn's method. The processes 

 are performed very quickly, and the formation 

 of magnetic oxide on the surfaces to be welded 

 (which interferes with the success of the opera- 

 tion when coal gas and air are used) is avoided. 

 The surface of iron heated by this means to weld- 

 ing heat comes out clean and free from scale. 



Attempts at welding by the electric arc have 

 not, according to Prof. Elihu Thomson, been sat- 

 isfactory. But electric welding is successfully 



performed when the heating effect of currents 

 traversing a solid metal conductor is made gradu- 

 ally to bring the metal to the working tempera- 

 ture. In the easily fusible metals, this tempera- 

 ture is below a red heat, and the process is there- 

 fore unattended with glow, which, however, ap- 

 pears with more refractory metals. All metals 

 so far tried have been welded by this method, 

 with varying degrees of perfection. The form 

 of the pieces to be tried is of little moment, pro- 

 vided they permit secure clamping for the pas- 

 sage of the current and for manipulation. The 

 surfaces to be welded should be held in firm con- 

 tact, while the heating may be regulated at will 

 or automatically controlled. Lead, tin, and zinc 

 are easily welded ; antimony and bismuth pre- 

 sent no great difficulties; aluminum demands 

 special precautions that can be readily taken; 

 manganese, oxidizable as it is, since it melts be- 

 fore it takes fire, is practicable. Brass and cop- 

 per require stronger currents than iron of equal 

 section, or other metals of less conductivity. Al- 

 though with most metals joints can be obtained 

 without the use of a flux, a flux is often desirable 

 for good work. A valuable peculiarity of the 

 electric process is its capacity to form joints even 

 where the metals may be coated with oxides in- 

 fusible at the temperature of fusion of the metals 

 themselves. The current has a kind of expul- 

 sive power to remove the metal sidewige from 

 the joint, and thus bring unoxidized, clean sur- 

 faces into contact at fusible temperatures. Soft 

 iron behaves well under welding, and the pro- 

 cess is easy and certain for all grades of steel. 

 Machinery is constructed in which the process 

 can be placed under automatic control. The 

 method has been found valuable in a great va- 

 riety of practical applications. In comparison 

 with the results of ordinary welding by the 

 blacksmith, electrically welded stock has usually 

 shown a somewhat higher percentage of strength. 



A new form of Siemens furnace, arranged to 

 recover waste gases as well as waste heat, was 

 described by Mr. John Head at the London meet- 

 ing of the Iron and Steel Institute, in May. The 

 chief peculiarity of its operation is the recon- 

 version of the waste gases into combustible gases 

 by being taken partly through an air regenerator 

 and partly under the grate of the producer, so 

 that they redistill the hydrocarbons from the 

 coal in fact, the gas producer utilizes the heat 

 formerly deposited in the air regenerators. A 

 steam jet is used for starting the action. The 

 new form of furnace has been applied to the 

 heating and welding of iron. It is to be used 

 for puddling, and for copper and steel melting. 

 Claims are made that it effects a saving in fuel 

 of about two thirds the weight, a reduction in 

 the weight of iron equal to 5 per cent., and a 

 saving in labor and repairs. 



METEOROLOGY. Temperature. " A 

 Study of Types of New England Weather," pub- 

 lished by W. M. Davis in the " Observations of 

 the New England Meteorological Society for 

 1889," has more particular reference to cyclonic 

 variations of temperature. One of the most dis- 

 tinct signs of the approaching winter season is 

 the growing frequency with which the regular 

 diurnal variation is obliterated by the cyclonic 

 variation. The usual rise from morning to early 

 afternoon, and the fall from that hour till the 



