510 



.LLrRGY. 



is decomposed again at 500* C. So that -i'.x.-r. like 

 .r proper! \ 



pnorosal ; ..mug 



Miiminuiu. -Almost : 

 aluminum 



ten r 



tin- introduction of the 

 -' I In- aluminum of 



,.,::,",,! ^.i- : . polled from Pram . 



where nanufaoured by the Seville prooew 



iiinum chloride liy I In- aid of me- 

 ,1111. niul was M.M I,. 



. he introduction of Cashier's im- 

 -vv* for the manufacture of sodium 

 jet ion of price toftfapoundpossibl 

 labery and Cowles prooeei i"ii in the 



. M) far that aluminum 

 was pp-duccd in the I'nited States cheaply <i 



\e out foreign competition. The mnnufai lure 

 f the metal has reached its present high develop- 

 untry by the aid of the process of 

 Charles M. Hall, in which the alumina, being held 

 in solution in a lath of molten fluoride, i- reduced 

 by electrolysis without decompovit ion ..r the liath. 

 so a? to allow practically of a continuous process, 

 by which a nearly pure product is furnished. While 

 the use of aluminum ipidlydur- 



; pa-t few Tears, some disappointment is felt 

 at the results ..f the more thorough knowledge of its 

 chant that hat been gained. Asa metal by 



aluminum i- proba: destined 



plant iron and steel in .structural work. Its coni- 

 paratively low len-ilc -tn-ngth. with i he extremely 

 narrow Timits ,,f heat between which it must be 

 ire homogeneous structure, will al- 

 ways make it too treacherous for such purpose. 

 On the other hand, the results obtained with alloys 

 of aluminum point to wonderful |Hissiliiliiies in the 

 future. S> far the alloy i 

 present results and the greatest promise is that wiih 



i. The addition of a few per rent, only of 

 nickel to aluminum greatly enhances the strength 

 and toughness of the metal and adds to its brillian- 

 cy without adding materially Jit. 



.utoii finds cadmium iodide a convenient 



r for aluminum. If it be fu-ed on an alumi- 

 num plate decomp. .-it ion of the -alt occurs long 

 before the melting point of aluminum is reached. 



result is generally the violent evolution of 

 iodine vapor and formation of an alloy of alumi- 

 num and cadmium on the surface of the metal. 

 The decomposition of the cadmium iodide is. h<>w- 



'. ..i rapid to be convenient, and the pulveru- 



vhite residue is in the way. These defects are 

 obviated by adding zinc chloride. The result, when 

 the salts are completely fused together, is a flux 

 which readily enables tin or other soldering alloy 

 to fuse perfectly with aluminum. 



In the Creoelius process for ca-ting liirht alumi- 

 num articles an iron mold with an ascensional feed 

 is used. It*- fore casting the molds are he.it. d i.. a 

 re aU.ve the melting point of the metal 

 that is to be poured into them. The melted metal 

 is poured in to a gate at the top of the mold, which 

 follows up the -hrinkage of the ra-ting. and the 

 whole u a r-K.lingehamlM-r through which 



ressed air , by the temperature 



is reduced very rapidly. 



authorities differing greatly as to whether 

 aluminum is acted UJK.H by nitric acid, special ex- 

 periments were math- by Pro! Th : Iman 



rmine the question. Bis results showed that 

 aluminum in the form of coarse turnings i- readily 

 acted upon by this acid, hot or cold, the solution <,'f 

 the metal being more rapid in nitric acid of specific 

 gravity 1'15 than with the stronger acid of specific 



if the metal is in thick plat- 

 n of the nitric acid i- much retarded. An c\- 

 -chutkin's statement 



that a lay.-r of nitric o\idc i- formed, protecting the 

 metal from further a-t i.-n.showeti that \\hile aiumi- 

 num in thin foil or .-a-il\ dis- 



: in either the hot or the cold acid solution is 

 !ed in the hot acid if the aluminum 

 in thick plate-, and under the -an 

 cu instances does not take place in the (old acid. 



Copper. In the mining, smelting, and refining 



i i .. Spil-bury "I . less! 



"iade in the past ten \. .n- than 



in tip B; mines which had been aban 



<loned are n. .u \\,.rked at a i>r<'lit : and the . 

 the metal has been con-iderably reduced. It is 

 hard for a ycr-on not actively engaged iii the met- 

 allurgy of copper to sin. 



invention or improvement which ha- more than 

 another contributed to these iv-nlK In the i 



copper diatriota the Improvements ha\e taken the 



direction of handling enormous quantities of ma- 



wiih the least jKissible labor. In ti 



(km of Montana ai id Ari/.ona. in addition 

 to tlie-e problem-, the com|. lex ami char- 



a-ter of the ore- has had to be taken into account 



The Mirce-sfiil malting if tln-se complex or. -. -ub - 



se(jiieiit enriching by the Bessenicri/ing pi<>< , .-..,;,,! 



finally parting and depositing the copp. c b\ the 



:1 electrol\li<- processes, have all come into 



il n-e during the decade. 



1'nder a ne\v pn.ce-s mentioned in "Industries- 

 and Iron," by which copper is ca-t pure, it i 

 that the metal ac<|iiiresan additional Jennie st i 

 < cut., and possesses a conductivit\ 

 nt. when compared with the best rolled ,,),- 

 The new metal appear- to carry the same eur- 

 Mth only one third the weight ordinarih 

 The change, which ; ted a- being eff< 



in the molecular structure of the metal, may i 

 counted for by the theory that the shape of the 

 cr\>taN ha- l-i-eii altered" so that their lin- 

 pa'rallel. and that the molecules arc .-. .n-e. jiidit ly 

 brought closer together and into more intimate 



. i with each other. 



As the distribution of the preriou- metal- and 

 impurities in copper is very uneven and irregular, 

 ordinarv methods of sampling bars an-: 

 un>aii-fartory result-. What is re.juired. .M 

 Keller says, is a form of sample bar in which the, 

 distribution shall be even. In pouring the ladle 

 must be hot enough to prevent any sculling, as the 

 liquid part is sure to show a different pi : 

 metal from that which solidifies on the ladle. A 

 sample bar (or plate) the thickness of which i- -mall 

 in comparison with the length and width, ha 

 di-ired form, us the concentration from side to ren- 

 arther than a distance equal to the 

 thickne-s of the plate. becau--at that moment the 

 entire plate will have solidified. The border of the 

 plate for a di-tance equal to the thickne-s ,,f j| will 



ar distribution, concentration hav- 

 ing taken plac" in one direction only. A correct 

 e will result if the plate be punched or drilled 

 through. 1" inches, 



-quare and one inch thick. Seekin_ r an explana- 

 tion of the irregular distribution <f impurities, the 

 auth< -ied by ex|MTiment that a dun 



I'l-er remained uniform in composition 

 when it had once been made -,, bv thorough agita- 

 tion and mixing. The different clement- -how dif- 

 ferent degrees of concentration, which correspond 

 :-t in the case of sulphur, with th'-ir 

 melting point-. The more readily fusible the 



.ness of distribution. 



lie weight and -pecific gravity do not appeal- 

 to have any special bearing upon the subject, but if 



