43 
in commerce owing to their white appearance deserve the 
attention of engineers. There is in this series an alloy to 
which we wish to draw special attention, viz., the alloy Cu 
Zn composed 
Per cent, of Copper 49.32 
,, Zinc... 50.68 
Although this alloy contains about 20 per cent, more Zinc 
than any of the brasses of commerce, still it is when carefully 
prepared far richer in colour than the ordinary alloys of com- 
merce, and it has also a high degree of hardness, this being 
three times as great as the calculated quantity. To enable 
engineers to form an opinion as to the value of this cheap alloy 
we give here the degrees of hardness of several commercial 
brasses. 
Weight 
Employed. 
Cast lron=l,000. 
Obtained. 
Calculated. 
“ Large Bearing” Copper, 82.05... 
♦Tin 12.83... 
Zinc 5.13... 
lbs. 
2,700 
562 
259 
“Yellow Brass” Copper 64.00... 
Zinc 36.00... 
2,500 
620 
268 
“ Pumps and Pipes ” Copper 80.00 
♦Tin 5.00 
Zinc 7.60 
Lead 7.50 
1,650 
343 
257 
* These Alloys contain Tin. 
ON BRONZE ALLOYS, 
Formulse of Alloys, and 
percentages of each. 
Weight 
Employed. 
Obtained 
Cast lron=l,000. 
Calculated 
Cast lron=l,000. 
lbs. 
Cu 
9.73 
Sn 
90.27 
400 
83.33 
51.67 
Cu 
11.86 
Sn^ 
88.14 
460 
95.81 
59.56 
Cu 
15.21 
Sng 
84.79 
500 
104.17 
68.75 
Cu 
21.21 
Sn, 
78.79 
660 
135.42 
84.79 
Cu 
34.98 
Sn 
65.02 
Sn 
51.83 
Cu, 
48.17 
Sn 
38.21 
C«3 
61.79 
> Brittle. 
Sn 
31.73 
Cu^ 
68.37 
Sn 
27.10 
CUg 
72.90 
/ 
Sn 
15.68 
Cu,o 
84.32 ... 
4,400 
916.66 
257,08 
Sn 
1 1.03 
CUi5 
88.97 ... 
3,710 
772.92 
270.83 
Sn 
8.51 
Cuao 
91.49 ... 
3,070 
639.58 
277.70 
Sn 
6.83 
Cu, , 
93.17 ... 
2,890 
602,08 
279.16 
