In operating with this, the author proceeded as follows: The funnel was partially filled with water, and hot water added until its temperature reached 43° C. (= 110° F). A sufficient quantity of the oil to be tested was placed in the glass vessel G, and drawn into the viscosimeter by gentle suction of the mouth until it exactly reached the line U, where it was retained, by a slight pressure with the thumb and finger, for five minutes, the temperature of the water in the funnel being kept constant. At the end of that time, after being sure that all the conditions as to temperature and quantity of oil were satisfied, the pressure of the thumb and finger was relaxed, when the oil began to drop through the lower end of the pipette.
The time required for the upper surface of the oil to fall from U to O was carefully ascertained by means of a "stop watch," and the number of seconds noted. In case of doubt the test was repeated.
The temperature of the water in the funnel was then lowered by the addition of ice, to 38° C. (= 100° F.), when the operation was again performed as just described. This was repeated at regular intervals of temperature down to 4° C. (= 40° F), when the water was again heated, the pipette thoroughly cleansed by introducing benzine into the pipette in a manner similar to that by which the oil was introduced. The surplus water which accumulated in the funnel was allowed to escape through the syphon by relaxing the lever of the pinching device. It is obvious that the number of seconds, in each case, corresponds to the viscosity. Other oils were put through the same course, the results obtained being shown in table XI.
RELATIVE VARIATIONS OF VISCOSITY OF OILS IN VARYING TEMPERATURES.
-----------------+---------------------------------------------- SYMBOLS | SECONDS REQUIRED FOR 1 C. C. OF OIL TO FLOW ACCORDING TO | THROUGH AN ORIFICE OF 1 MM. (= .04 IN.) TABLE III. | ---------+-------+----+-----+-----+-----+-----+-----+-----+----- | CENT. | 4.5| 10 | 15.5| 21 | 26.5| 32 | 37.5| 43 TEMP.{ A} +-------+----+-----+-----+-----+-----+-----+-----+----- | FAHR. | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 ---------+-------+----+-----+-----+-----+-----+-----+-----+----- E. K. w. | 25 | 20 | 17 | 15 | 10 | 8.5| 7 | 6 W. F. N. w. | 27 | 20 | 14 | 11 | 9 | 8 | 7 | 6 D. C. S. w. | 32 | 23.5| 19 | 15 | 12.5| 11.5| 9.5| 8 D. C. S. ch. | 28 | 23 | 17 | 14 | 11.5| 9 | 7 | 6 D. C. S. cl. | 29 | 20 | 17 | 14.5| 11 | 8.5| 7 | 6.5 W. C. w. | 24 | 20 | 18 | 13 | 11.5| 10 | 8 | 7 B & K. w. | 46 | 35 | 25 | 20 | 17 | 15 | 11.5|10 S. B. & Co. w. c.| 21 | 16 | 11.5| 10 | 9 | 8 | 7 | 6.5 C. L. Co. w. | 14 | 10 | 9 | 6.5| 5 | 4.5| 4 | 3.5 C. L. Co. No. 1. | 32 | 28 | 12.5| 10 | 8.5| 7.5| 6.5| 6 Glyc. | 19 | 13 | 10 | 9.5| 7.5| 6.5| 5.5| 5 Alb. f. | 25 | 19 | 16 | 13 | 10 | 8 | 6.5| 5.5 -----------------+----+-----+-----+-----+-----+-----+-----+-----