ON THE ACTION OF AIR AND WATER UPON IRON. 47 
Gray Cast Iron. Skin removed by Planing. 






7. 8. 9. 10. 11. 12. 13. 14, 
er 
ears 
Weight of | Total loss | 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 Surface Character of Corrosion. 
in Grains. | 539 days’ in inch of | Standard ab- in 
exposure. | 539 days. | Surface. Bar, sorbéd. | 732 days. 
33750 | 33294 456 7015 0:791 0: 9526 | Uniform minute pitting 


Gray Cast Iron, protected by Paints or Varnishes. 







‘49594 | 42409 | 185 | 2642 | 0-298 | 0 | 3-588 
42644 | 42620 24 | 0-342 | 0-038 | 0 | 0-464 
42399 | 42349 50 | 0-714 | 0-080 | 0 
42007 | 41974 33 | 0-471 | 0-053 | 0 | 0-639 
42004 | 41971 36 0514 | 0-057 | 0 | 0-707 
1-969 
_ Box g. No. 6. Class No. 8. 








Condition of surface of Specimen after 539 days’ exposure. Order of Protective Power. 



| Surface uniformly corroded ..........:cseeyssssseqseeeseeeeeess|esegeeeeeees 
| Corroded locally in pits, where paint gone ........-..see-[esenseeereee 
Rusty spots, chiefly at the edges..........ssssccesssececseece[eonseccreees 
Rusty spots, chiefly at the edges. .............ccsecceceseetee[esesceeeuees 
| Surface uniformly corroded............c00..seeeeeeeeeees 
| Corroded locally in spots............cccccessseeseeeseeees 
No corrosion visible.............seccece0s ayes une. at Aaeeasieo les pp mee ian 
A few rusty spots at the edges.........+. sae Fab edasbdcenacs|carade abate 
:! Corroded locally in spots............c00 co, Le A EERBERCE pape Bere Rae ree 
A few rusty spots at the edges....... BUPARAR Benes Fa ee a Senet 

on FPwWNORWPOO 

