This coat was followed by one of the following composition, tinted blue:
| Zinc oxide | 60% |
| Gypsum | 20% |
| Silica | 20% |
| Ground in linseed oil with 12% of turpentine and drier. | |
Fair results shown during first year, but a breakdown occurred during the second year, and cracking and scaling resulted.
Test No. 9. This test was a duplicate of No. 8 with the addition of 5% of zinc sulphate solution emulsified into the primer.
Slightly superior to Test No. 8.
Test No. 10. Primed with a white paste paint thinned with turpentine. Second coated with same paint tinted blue.
Formula of Paste
| Zinc oxide | 40% |
| Whiting | 30% |
| Silica | 20% |
| Alumina and gypsum | 10% |
| Ground in 16% of linseed oil vehicle. | |
Scaling and peeling due to lack of binder and use of saponifiable oil resulted during the first six months’ exposure. Entire destruction of coating at end of two years.
Test No. 11. Primed with a white mixture, and second coated with the same mixture tinted blue.