TABLE VII.
Relative Viscosity and Gumming of Oils.
Temp. 15.5° C. = 60° F. Inclination 6 degrees. Time 7 days.
| SYMBOLS ACCORDING TO TABLE III. | DISTANCE IN CM. TRAVELED BY OIL AT THE END OF EACH DAY. | WIDTH OF TRACK. | ||||||
| DAYS. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | |
| E. K. w. | 16 | 18 | Stat. | ... | ... | ... | 18 | Medium. |
| W. F. N. w. | 15 | 16.5 | 18 | 19 | 20 | Stat. | 20 | " |
| W. C. w. | 17.5 | 19 | 20 | Stat. | ... | ... | 20 | Narrow. |
| B. & K. w. | 12.5 | 15 | 17.5 | 20 | Stat. | ... | 20 | " |
| C. L. Co. w. | 7.5 | 10 | 12.5 | 15 | 17.5 | Stat. | 17.5 | Very wide. |
| C. L. Co. No. 1. | 15 | 16.5 | 18 | Stat. | ... | ... | 18 | Medium. |
| Glyc. | 15 | 16.5 | 18 | Stat. | ... | ... | 18 | " |
| Sp. | 0 | 2.5 | 5 | 7.5 | 9 | 10 | 11 | Narrow. |
| Ol. | 5 | 6.5 | 7 | Stat. | ... | ... | 7 | " |
Table VII not only shows the relative viscosity of the various oils, but also their tendency to gum or dry (79.) The "width of the track" left by the oil is an indication of the cohesion (20) and adhesion (21) which exists, respectively, in the oil and between the oil and the glass. A narrow track denotes great cohesion and little adhesion; a wide track denotes great adhesion and little cohesion; while a medium track indicates that both properties are more nearly equal.
If an oil possess great adhesion and little cohesion it is more liable to resist the tendency to be squeezed out of bearings, but it is also more likely to spread.
Another test made in the manner just described (table VII) gave results as shown in table VIII: