ON THE ACTION OF AIR AND WATER UPON IRON. 45 
of Experiments. 
and Wrought Iron freely exposed to air and moisture under the ordinary 
at Dublin. 
Dublin, and exposed on the ist day of August 1840. Removed, cleaned and weighed on 
hence exposed for 539 days. 
Annual Mean Temperature...... 50°24 Fahr. 
Annual Mean Pressure .......++. 29°60 Inches. 
Annual Mean fall of Rain ...... 27°33"... 
East and West, and South-West. 
Scotch Cast Iron. 













Weight of | Totalloss} Loss of Loss of | Weight| Loss per 
Weight of | Specimen by Weight | Weight of square inch 





| Specimen after Corrosion | per square | referred to} Water | of et Character of Corrosion, 
in Grains. | 539 days’ in inch of | Standard ab- 
{ exposure. | 539 days. | Surface. Bar. sorbed. |. 732 ae 
ir i ; 
43149 | 42835 314 4-485 0-506 0- 6128 | Uniform minute:pitting |) 


43939. | 43720 219 3128 0-352 0- 4:099 | Uniform minute:pitting’|| 

Welsh Cast Iron. 




‘42289 | 41885 354 5057 | 0570 0 6-867 | Uniform minute pitting || 
43239 |. 43095 144 2-057 0:232 0° 2-793 | Deeply pitted 
| 
Staffordshire Cast Iron. 
43735 | 43491 244 3°485 0:393 0: 4-732. | Uniform 
43562 | 43541 21 0:300 0-033 0 0-407 | Local pitted : 


Trish Cast Iron. 





[ars 41435 | 310 | 4-428 | 0-499 | 0: | 4-428. | Uniform minute pitting 
| 43465 | 43395 70 | 1300 | 0-112 | 0+ | 1-357 | Local pitted, slight ~~ | 
Se 
ae 
| 43325 | 43181 | 144 | 2-057 | 0232 | 0+ | 2-793 | Local pitted, slight 
| 42241 | 41898 | 343 | 4900 | 0552 | 0 | 6-654 | Uniform minute pitting 







: / 41341 41038 303 4328 | 0-488 0: 5-877, | Uniform minute pitting 
Standard Bar of Wrought Iron. 



Minute pitting most at 
- 
anid ends, fibre visible 

24018 | 256 | 5-818 | 0656 | . | 7-901 

