ee 
= 
ead or eee Pee. oe Wee oe ee 
* 
Storer on the Alloys of Copper and Zinc. 289 
“This alloy readily admits of being sa pong! hot or cold, and m 
be subjected to the operations of hammering or drawing without det 
ment, while alloys containing on! aher’y e mf ore copper can be 
rolled hot only when the sheets are raised to a very high tettsaP atte err 
“Tn the preparation of the alloy of 60 per cent copper, now so exten- 
sively used for sheathing vessels under the name of Muntz’s sheathing or 
yellow-metal,—also known as malleable brass,—it is the custom of found- 
to reserve a portion of the zinc whic been weigh a 
charge, until the alloy in their pots or furnace has become sufficiently 
ot ; last portions of zinc are then added in small pieces, a sample of 
the alloy being tested after each such addition. This is done by aipping 
out a small portion of the melted mass and pouring it into a mould ; 
little ingot, five or six inches long by an inch or less in thickness, is thus 
obtained, which after cooling, is broken on an anvil, and its fracture ob- 
served. If this does not exhibit a smooth and homogeneous surface, more 
zinc is added to the allo oy. The accuracy with which an experienced 
workman can thus obtain the desired alloy i is truly astonishing, the more 
=. since this homogeneous alloy is confined within very narrow 
eee eed remark in this connection, that I have repeatedly obtained crystals, by the 
a iors pe aera cooling, from portions of melted yellow-metal taken from the 
funders pai at the Becket it had afforded them a satisfactory test. These crys- 
oo from those obtained by myself from alloys of almost 
« position 
Although! as mn es ‘been es the tendency to _ fibres seem ve ceased 
hs : 60 per of copper, I cannot but shink that 8 “limit of 
influence is ay aan Fee than the “test” of yellow-metal founders would 
_ ¥eem to indicate. In the circumstances under which this test is applied, it is doubt- 
true that no fibres are formed; but it is a matter of experience with manufae- 
Beery Qo 
oO 
Be 
c 
= 
a 
si HF 
“a ihe : 
2g 
R34 
8 
a 
a 
. a n 
Ng would soon be destroyed ;—not only because the salt water would come 
contact with a interior portions, but also ke the individual ro eg in fibres 
matter cy woul d doubtless resist its action more completely than the amorphous 
Would be attached to them or contained in their interstices ; from this a voltaic action 
Produced, which could not fail to promote the corrosion mn of the alloy.” 
(To be concluded.) 
