5 1 L' 



MKTALLl BOY. 



the long range of temperature during which solidi- 

 fication takes place should IK- called tin- true incit- 

 ing or fnv/.ing |M.int of the alloy. In f 



r< alloys with inorv than on< |'"iiit 



have i red to. Tin- temperature al which 



one constituent begins to crystallize out was 



the I. (Hiint. aiil the teiui 



which the eutectie alloy x.luiifles was called the 



lower freezing i M>int. It may app-ar a 1 



Ugh these point- mu-t be the bcginnii 



:ig of one cont inuous process of --iiilili. 



hut a . i In- inilial 



.- ; .-. . . Qtl aff !ndicat< -1 !> MOt> 



rateanddi-tmct evolutions of heat, they uprightly 



i to be separate, and n<>t merely stages 

 single operation. The fact that the l'cad-tin 

 has more than one freezing |...int is ,,f industrial 

 importance, for on it depends the facility with 

 which an artificer can "wi|*- a joint " with plumb- 

 ,;ain- lltJ per cent, of lead. 



ami its pasty condition when used is due to the fact 

 that it ha* i points of -olidifica- 



t ion. the alloy consisting of granule.- of solid lead 

 in a fluid mother IK 



In the /.in. -copper series of alloys, the upper cu- 



prol.al'lv consists of a inixtnVc of copper \\ ith 

 the OOmpOUM Cu/n. The mixture of these soft 

 and hard substances produces great strength, as i- 



it from the fact that tl. ->t alloy of 



this series consists almost entirely of this eutectic; 

 tint the presence of a eutectic naturally diminishes 

 the extensibility of a ma which contains m.re 

 than a small amount of it. Itoth the annealing' and 

 the work n bra-s materially increase its 



strength : and this fact is of industrial importance, 

 AS it suggests that for certain purposes a brass con- 

 taining nearly 50 per cent, of the cheaper metal 

 may by suitable treatment be endued with proper- 

 ties which render it as useful as one richer in copper: 

 its extensibility, however, would be small. Alt hough 

 brass containing from 60 to 70 per cent, of zinc i- 

 extremely weak, further additions of zinc are ac- 

 companied by a partial return of strength, which 

 appears in some way to be connected with the prc>- 

 ence of free zinc. Each apex of a curve represent- 

 ing mechanical properties seems to be in some way 

 connected with a point on the freezing-point curve 

 where the joints of solidification tend to unite. In 

 the copper-/inc series the connection is complicated 

 by the simultaneous presence of more than one <n- 



: but in the lead-tin series the maximum 

 _-'h is possessed by the eutectic alloy of the 

 series. In the copper-tin series the connection be- 

 tween a maximum strength and the union of the 



tuentsof a given alloy in a single j>oint. though 

 generally clear, is sometime- masked by the wide 

 range through which the eutectics extend. 



As one fact which has been made more and more 

 prominent in the alloys researches of later 

 I)r. Ktard. of the Ecole Polytechniqu 



'. influence of very small quantities, the 

 microj,la>ins ,, r chimions of some kind. A j 

 ent study of steel has enabled the chimionic influ- 

 h quantities of carbon, silicon, or phos- 

 phorus as might IK> expressed in atomic weights. 

 for carbon and iron, by the formula Fe, ,,( 

 recognized: and whatever mav be thought of this 

 inadmissible formula, the relation of i atom of 

 carbon to I.INNI atom* of iron remains a fact. Such 

 quantities are actually employed in metallurgy 

 when varieties of steel possessing certain pn.| 

 are required. An attempt has been made to ascer- 

 tain how far the properties of metallic masses are 

 dependent on atomic movement and molecular 

 grouping. iianical properties of all" 



definite series of metals have therefore assumed 

 less prominence than the principles which affect 



generally. While the practical bearing of 

 the in- , seemed to In- s.-nie\\hat 



ibUaning of the HI ween 



alloys and saline solutions has been eminently 



fruitful of practical results; for it 1m- enabled the 



J properties of alloys to be explained, 



qua- 

 tion possessed by saline solution.- while 



i Ms in reject in;,' a certain quantity. 



n of the DiaSS, and 



distributing or relegating it to a definite p.,xj| jon in 



to individ- 

 ual crysta^ ,mla- 

 menta'l imi in determining the mechanical 

 of iron and steel, and of | rally. 

 King the problem ,,f the c.mstituli' 

 from the atomic point of view has enabled the in- 

 fluence exercised by the relative atomic \olumesof 

 the allo\ed metals upon the mechanical |>i"j 

 of th, :. h may 

 now be accepted a- proved thai the inllucn. 

 cried by an element added to a ma-s b.;i 

 relation to its atomic volume. The original prob- 

 lem pn.po- :.-idcration by the Allo\ 



: Committee, "An- the mechanical properties 

 of metals and their alloys connected with their 

 atomic volumes f" has been definiti !\ answered in 

 the allirmative by this and I D I he 



Huropcaii ('(.ntinent and in America, The evi- 

 dence which has been gathered that then- i- a con- 

 stant and active molecular movement in solid- - -an 



hardly fail to be of importance in all indu>n 



which metallic alloys arc employed. 



In the. manufacture of ph<pln>r bronze a 

 scribed by Max A. \\"icklmr>l the phosphoric added 

 to deoxidi/.e the metal may be introduced a- phos- 

 phorus or as a high phosphorus alloy, called hard- 

 ener." Tins contains ' p--r cent <-r pho-pi 

 with copper ami tin in the ratio of 8 to Land is 

 made by melting 1)0 pouiid> of copper and adding 

 11 pounds of t in. Seven pound> of phoephoiUI are 

 put into a dilute .solution of blue vitriol, and kept 

 there till they arc coated with metallic copper. 

 This protectsthe phosphorus when it is dried in tin- 

 air. After drying, the sticks of copper-plated phos- 

 phorus are iniroduced into the melted bron/e. two 

 or three at a time, and held to the surface of the 

 metal by a cup-shaped tool. The phosphorus melts 

 and combines with the metal at once, to form t he 

 "hardener." Phosphorus ha-theelTect of harden- 

 ing bronze, while it also make- it more fluid. The 

 important property of iiho-phnru- r, to 



deoxidize the meta'l. and it docs this effect iveh. 



In much of the manganese bron/e used by : 

 drymen the maiiL r anc-c js added in the -ha; 



iiaii-ancse. which necessarily intr>du.-- con- 

 siderable iron into the bronze. This iron i- regard- 

 ed by Mr. !'..!. 1 >a\is as injurious, ami the b- 

 ; ie as more readily corroded and not nea; 

 strong, tough, and din-tile a- bron/e, that does not 



ii iron. |',y ii-ing a ri<-h alloy .,f p 

 and copper, containing no iron, or other impurities. 

 which is now ofTen-d. a pure n 

 any desired grade can be pro-iired. One of the 

 best and i.ninzes a very stron-. ton-h 



metal can be made of copper, 53 per cent. : /inc. 

 r cent.: manganese. :;:.) percent.: and alu- 

 minum. I'-' aluminum 

 is essential to getting solid <-a-!iir_-. For lulling 



icets. i,, which form maiigane-i- bn-i.. 

 for minin_ ontaining 



1 manganese and les- /inc. A sub- 

 stitute for(Jcrman silver, composed of copp r. 

 percent.: manganese, 18'50 percent.: /inc. i:; per 

 : and aluminum. I"-.'-") per cent., is of good col or, 



nan silver closely, is -iron-, ha 

 perior casting qualities, does not corrode readily, 



