TABLE V.
Action of Oils on Brass.
Temp. 5.5° to 21° C. = 40° to 70° F. Time 25 days.
| SYMBOLS ACCORDING TO TABLE III. | CONDITION. | |
| OF OIL. | OF BRASS. | |
| E. K. w. | Very Light Brown. | No change. |
| W. F. N. w. | " " " | " " |
| D. C. S. w. | " " " | " " |
| D. C. S. ch. | " " " | " " |
| D. C. S. cl. | " " " | " " |
| W. C. w. | No change. | " " |
| B. & K. w. | " " | " " |
| S. B. & Co. w. & cl. | " " | " " |
| C. L. Co. w. | " " | " " |
| C. L. Co. No. 1 | " " | " " |
| Glyc. | " " | " " |
| Alb. f. | " " | Very light brown. |
| Alb. s. | " " | Unaltered. |
78. The Effect of Oils on Steel, with a view of ascertaining their rust preventing properties, especially to see if the treatment of hairsprings with a very slight film of oil (56), would prevent rust in warm, damp climates was ascertained by the author, as follows: Each of twelve brass pins, stuck vertically in a block of wood, had a colleted hairspring on its upper end. The block of wood was allowed to float in water and covered by a glass. One hairspring was left as it came from the factory, while each of the others had been treated with a solution of porpoise jaw oil and benzine, varying proportions of one to ten per cent of oil being used, the balance being benzine. The hairsprings were dipped into the solution, and, on withdrawing, were immediately placed between two folds of soft linen cloth. In any case not enough oil remained on the hairsprings to cause the coils to adhere. One per cent of nitric acid was added to the water, and after ten days the hairsprings showed on examination that they had rusted in proportion to the amount of oil that had been used. Another trial, without acid in the water, and with one hairspring treated with ether, one with benzine, one each with one, two, five and ten per cent of porpoise jaw oil in benzine, and one each with the same quantity of mineral oil in benzine, showed after thirty days that the hairspring treated with ten per cent mineral oil was slightly rusted, while those treated with ether and benzine were badly rusted, and all the others were rusted more or less.
79. The Gumming and Drying of Oils is a very important consideration, the former being caused by oxidation, while the latter is due to evaporation.
In order to determine these properties in various oils the author used a number of watch glasses, their convex side being glued to a board. Two drops of oil were placed in each watch glass and spread over its concave surface, and the board placed in a covered box in which suitable air holes had been made, and allowed to remain in a temperature varying from 21° to 37.5° C. (= 70° to 110° F.) for 100 days, and at the end of that time the results shown in table VI were noted.