------------------+------------------------------------------ SYMBOLS | DISTANCE IN CM. ACCORDING TO | TRAVELED BY THE OIL AT THE END TABLE III. | OF EACH DAY. ------------------+----+----+----+----+----+----+-----+------ DAYS. | 0.3| 1.3| 2.3| 3.3| 4.3| 5.3| 6.3 | 7.3 ------------------+----+----+----+----+----+----+-----+------ E. K. w. |14 |23 |26.5|28.5|29.5|31.5|32.5 |33 W. F. N. w. |12.5|20 |26.5|29 |31 |32.5|33.5 |34 W. C. w. |19 |24 |26.5|28 |29 |30.5|32 |33 B. & K. w. |14 |17.5|25 |27 |29.5|31.5|33 |33.5 S. B. & Co. w. c. |10 |20 |26 |26.5|27 |27.5|28 |28.5 C. L. Co. w. |29 |38 |40.5|42.5|43 |43.5|Stat.|43.5 C. L. Co. No. 1. |17.5|23 |27 |28 |29 |30 |31 |32 Glyc. |17.5|23 |28 |30 |32 |34 |35 |35.2 Alb. f. |15 |20 |29 |33 |35 |37 |38 |38.5 ------------------+----+----+----+----+----+----+-----+------ The author once heard a watchmaker say to a customer, when the latter called for a clock which had been left for repairs, "I have cleaned your clock thoroughly; and, as you are a good customer, I made as good a job of it as I could. _I even oiled it with watch oil._" This watchmaker evidently _thought_ he was right. It is hardly necessary to mention that a stock of oils of different viscosity should be kept on hand and intelligently used; the different bearings in any time keeping mechanism requiring oils of different viscosity. It is not to be supposed that the author means _each_ bearing in a watch is to have a separate oil applied; but a distinction should be made between the light and heavy pressures. ~82. The Effect Of Heat On Oils~ is very marked in all cases; some oils being much more subject to change than others, in viscosity and other properties, under the influence of an increase of temperature. The lubricating power of an oil is decreased, while its tendency to spread is increased, with a rise of temperature. In order to ascertain the relative values of various oils in this respect the writer used a plate of glass 28 cm. x 40 cm., placed it flat on a table, and, depositing one drop of each oil near one of its longer edges, allowed it to remain in a temperature of 21° C. (= 70° F.) for 30 minutes. At the end of this time the glass plate was placed in a vertical position, with its edge near which the drops of oil had been deposited uppermost and horizontal. The time required by each oil to run down to the bottom, a distance of 25 cm., was noted. The width of the track, at a point 3 cm. from the location of the drop at the start, was measured when the oil had passed that point, and again measured _at the same point_ when the oil had reached the bottom.