107 
Table D. 
Comparative Eepect op Sulphuric and Hydrochloric Acids on 
Unannealed Charcoal Iron Wire. 
De-icription. 
Diame- 
ter 
inch. 
Ulti- 
mate 
Elonga- 
tion. 
Decrease 
in 
ditto. 
Break- 
ing 
Strain. 
Break- 
ing 
Strain 
per sq. 
inch. 
De- 
crease 
in 
ditto. 
No.of 
tests 
ofwh. 
result 
is a 
mean 
Charcoal Iron before 
immersion in acid. . . 
•049" 
2-3% 
lbs. 
147-3 
lbs. 
78,200 
lbs. 
3 
Ditto after 12 hoiu’s 
in hydrochloric acid 
and subsequent 5 
hours in air at a 
temperature ofl2°C. 
•047" 
1-17% 
1-13% 
122-7 
71,930 
6,270 
3 
Last piece after being 
on hot plate for 5 
days at a tempera- 
ture of 40 — 140°C... 
•047" 
3-5% 
_l-2% 
81-3 
47,954 
30,246 
3 
Charcoal Iron after 1 2 
hours in sulphuric 
acid and subsequent 
5 hours in air at a 
temperature of 12°C. 
•045" 
1-3% 
1-0% 
98- 
61,800 
16,400 
3 
Last piece after being 
on a hot plate for 5 
days at a tempera- 
ture of 40— 140°C... 
•045" 
4^0% 
-1-7% 
104-6 
65,995 
12,205 
3 
1 
All the above 15 tests were made from one coil. 
Permanent decrease in B. strain after prolonged 
immersion in hydrochloric acid=30,2461bs. per sq. in. 
,, ^ ^ ,, sulphuric „ =12,205 „ „ „ 
„ increase in ultimate elongation after pro- 
longed immersion in hydrochloric acid=l'2 per cent. 
„ „ „ sulphuric „ =V7 „ 
