7. Should be unaffected by ordinary me-

chanical abrasion.

8. Should wear evenly.

9. Should fail by gradual wear, not by dis-

integration.

10. Should leave a good surface for re-

painting.

11. Should not require an unreasonable

amount of skill or muscle in application.

12. Should be homogeneous.

13. Should dry fast enough.

14. Should not be readily ignited.

15. Should. have power to absorb and

remove moisture or dampness from

the metal.

16. Should have properties that will pre-

vent corrosive action of traces of water

in contact with the metal.