The figures in the last column denote the apparent relative viscosity, as ascertained by inverting the test tubes repeatedly.

[Ill.u.s.tration: Fig. 15]

Again, even if the oil were viscous enough in high temperatures to resist the tendency to be "squeezed" out of the bearings, the _rate_ of the timepiece would be seriously affected by the variation of solid and fluid friction--especially the latter--caused by a variable viscosity of the oil.

When a watch, chronometer or clock has been so adjusted as to keep a _maximum even rate_, the oil is one of the factors of the variation which has been overcome; and it is obvious that if another oil be used, in which a greater or less variation of viscosity exists than in the oil with which such timepiece was lubricated prior to adjustment, the variation so produced will be more or less observable.

It is, then, evidently necessary to be able to ascertain, with the greatest possible exactness, what change in this respect is produced in the various oils by a change of temperature. The means previously given (81-83) have their value; but when supplemented by a method for determining the particular property under consideration, the results obtained are exceedingly interesting and valuable. On account of the importance of this matter the author has made investigations in this direction, using a "viscosimeter" as shown at Fig. 15, and of which the following is a description:

AA represents an ordinary retort stand, with adjustable arms, BB, for holding in position the thermometer C, and the funnel DD capable of holding about one pint of water. EE is the viscosimeter proper, a gla.s.s tube, swollen at the lower end, and terminating in a circular orifice of 1 millimeter (= .04 inch) in diameter;[25] being a "pipette" holding one cubic centimeter of oil between the dotted lines U and O.

F is a flexible gum elastic tube fitting with an air-tight joint to the upper end of the gla.s.s tube. The funnel is closed at its lower end by a tightly-fitting cork H, in which an opening is made, through which opening the pipette pa.s.ses and projects slightly below. G is a small, shallow vessel, preferably of gla.s.s, of sufficient capacity to receive the contents of the pipette. S is a syphon composed of a gla.s.s tube in two sections--united by a short piece of rubber tube on which the device P pinches by the adjustment of the lever L--the bent section beginning near the bottom of the funnel, while the straight section terminates below the level of the table on which the retort stand is placed.

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 quant.i.ty of the oil to be tested was placed in the gla.s.s 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 quant.i.ty 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 acc.u.mulated 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.

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 -----------------+----+-----+-----+-----+-----+-----+-----+-----

[Note A: The readings of the Centigrade and Fahrenheit scales given here are not exactly equivalent; but they are near enough for all practical purposes.]

~85. Mixed Oils~ have been tried by many who have been desirous of obtaining a better lubricant. A mixture of different kinds of animal or vegetable oils--or a combination of both--has usually proved worse than any single one of the components; as, when it is known that "alterations[26] of composition occur in the animal and vegetable oils with exposure to air and light and with advancing age" (74-2), it is obvious that this chemical action is accelerated by a mixture.

The mineral oils are not subject to such alterations to any serious extent; and, when they are compounded with animal or vegetable oils, the resulting mixture partakes of the good qualities of both, according to experiments which the author has made. It would make this paper[27] too lengthy to insert the results; however, a future opportunity may not be wanting.

~86. Various Manufacturers~ of watches, chronometers and clocks, have favored the writer with more or less valuable information in answer to queries on the subject, which has been tabulated and which is shown in table XII.

It is necessary to know just what kind of oil has been used by the manufacturer of a time piece for three reasons:--

(1.) If some of the bearings need a small quant.i.ty of oil, being otherwise in such good condition--because of never having been used, in fact "new"--that it is unnecessary to take all the mechanism apart and clean it, it is very important that the operator know what kind, or variety, of lubricant has been previously used, in order not to "mix oils;" or, if a mixture is thus made, to make it intelligently. (85.)

(2.) When the oil which has been applied in the factory has not performed its functions properly in any part of a time piece, it is necessary to know what particular variety of lubricant has been used in order to subst.i.tute an oil which possesses the properties lacked by the oil previously used. (61.)

(3.) In a watch which has been so adjusted as to keep a maximum even rate, the oil is one of the factors of the variation which has been overcome. It is necessary, then, on putting the watch in order, to employ a lubricant which possesses the same variation of viscosity as the oil which was used during adjustment. (84.)

Some other interesting facts are shown in table XII, as well as the foregoing. The queries were as follows:--

QUESTIONS ASKED.

1. What oil do you use?

2. What oils have you tried?

3. What has been your experience with mixed oils?

4. Do you use the same grade of oil on all parts of your ----?

5. If not, what is your practice?

6. What amount of oil do you use annually?

The answers are given in Table XII.

~87. Impurities in Oils~ and all foreign matter exert a very injurious effect. The method of sealing the bottles with sealing wax or gum labels should be avoided; the former, as the wax is brittle and liable to break in very fine pieces which lodge around the cork from whence they get into the oil; and the latter because the gum with which it is caused to adhere remains on the bottle, only to be absorbed by the oil.

Paraffin wax makes a very good sealing material, as it is not brittle, and keeps the oil protected from the air. An extra long cork should accompany each bottle.

TABLE XII.--ANSWERS TO QUESTIONS.

=============+==========+==========+=========+=====+==============+======== MANUFACTURER.| 1 | 2 | 3 | 4 | 5 | 6 -------------+----------+----------+---------+-----+--------------+-------- | | | | | Heavier oil | American | | | | | on barrel | 8 Waltham |Several. |Several. | Small. | No. | arbors and | quarts Watch Co. | | | | | winding | | | | | | Wheels. | -------------+----------+----------+---------+-----+--------------+-------- | |Kelley"s. | | | Light oil on | Elgin |Smith"s on| Cook"s. | | | escapements, | National |fine work.| Nye"s. | | No. | and oil with | 1-1/2 Watch Co. | Nye"s. |Wheeler"s.| | | more body in |gallons.

| |Smith"s. | | | mainspring | | | | | | boards. | -------------+----------+----------+---------+-----+--------------+-------- Hampden | | |Unsatis- | | | Watch |Kelley"s. |Kelley"s. | factory |Yes. | | Co. | | | | | | -------------+----------+----------+---------+-----+--------------+-------- Illinois | |Kelley"s. | Do not | | | Watch | Nye"s. | Cook"s. |use Mixed| | | 3 Co. | | And | Oils. | | |quarts.

| | others. | | | | -------------+----------+----------+---------+-----+--------------+-------- | | | | | Chronometer |1 gross New | | Nye"s. | | | oil on stem- |bottles Columbus | Nye"s. |Kelley"s. | None. | No. | wind and do |regular Watch Co. | | | | | no experi- | size.

| | | | | menting. | -------------+----------+----------+---------+-----+--------------+-------- | | | | | Watch oil on | New York | | | | |train pivots, | 2 Standard |Kelley"s. |Kelley"s. | None. | No. | and clock |quarts Watch Co. | | | | | oil on stem | each.

| | | | | wind. | -------------+----------+----------+---------+-----+--------------+-------- | |Kelley"s | | | | Rockford |Kelley"s. | Ayer"s. | |Yes. | | Watch Co. | |Guyjers? | | | | | |Smith"s. | | | | -------------+----------+----------+---------+-----+--------------+-------- Trenton | Nye"s. | | |Yes. | | Watch Co. | | | | | | -------------+----------+----------+---------+-----+--------------+-------- | |Kelley"s. | | | | Waterbury | Smith"s. | Nye"s. | Not a | | | 1 Watch Co. | | Smith"s. |Success. |Yes. | |gallon.

| | And | | | | | | others. | | | | -------------+----------+----------+---------+-----+--------------+-------- | | | |Yes. |Watches, light| | | | | | grade. | Seth Thomas | Nye"s. | Most | None. |Yes. | Clocks, | Clock Co. | | others. | | |medium grade. | | | | |Yes. |Tower Clocks, | | | | | | heavy grade. | -------------+----------+----------+---------+-----+--------------+--------

TABLE XII.--ANSWERS TO QUESTIONS.--CONTINUED.

-------------+----------+----------+---------+-----+--------------+-------- Manufacturer.| 1 | 2 | 3 | 4 | 5 | 6 -------------+----------+----------+---------+-----+--------------+-------- | | Steven- | | | On all bear- | | | son"s. | | |ings the same | {1}|Sine Dolo | Black- | None. | No. | oil, but on | 1 | | fish. | | | mainspring |gallon.

E. Howard | |Porpoise- | | | a rock oil. | Watch & | |jaw. Rock.| | | | Clock Co. +----------+----------+---------+-----+--------------+-------- {2}|Kelley"s. | | None. |Yes. | | 1 | | | | | |gallon.

+----------+----------+---------+-----+--------------+-------- {3}|Rock Oil. | | Satis- |Yes. | | 10 | | |factory. | | |gallons.

-------------+----------+----------+---------+-----+--------------+-------- | | | | |Light oil for | H. H. Hein- | |Every kind|Unsatis- | | small pivots | rich,Chrono- | Stull"s. | in the |factory. | No. | and heavier |1 pint.

meter Maker. | | market. | | |oil for larger| | | | | | pivots. | -------------+----------+----------+---------+-----+--------------+-------- | | Stull"s. | |Yes. |A light oil on| New Haven | Stull"s. | Black- |Unsatis- | |clock-watches.| 20 Clock Co. |Kelley"s. | fish. |factory. +-----+--------------+gallons.

| |Porpoise. | |Yes. |A heavy oil on| | | | | | clocks. | -------------+----------+----------+---------+-----+--------------+-------- Ingraham | | Rock. |Unsatis- | | | 12 Clock Co. |Porpoise. | Mixed. |factory. |Yes. | |gallons.

| | | | | | -------------+----------+----------+---------+-----+--------------+-------- | | Stull"s. | | | | Waterbury | Stull"s. | Smith"s. | None. |Yes. | | 15-20 Clock Co. | | Steven- | | | | gals.

| | son"s. | | | | -------------+----------+----------+---------+-----+--------------+-------- Wm. L. Gil- | | Nye"s. | | | | bert Clock | Nye"s. | Smith"s. | | | | 10-12 Co. | |Kelley"s. | | | | gals.

| |Comstock"s| | | | -------------+----------+----------+---------+-----+--------------+--------

[Note 1: Watch.]

[Note 2: Regulator.]

[Note 3: Tower Clock.]

Then again some workmen leave the oil bottle standing open, which is obviously a very careless proceeding. The author has seen a bottle one quarter full of dust, the oil still being used from the top. When oil is to be placed in the oil-cup, it should be done by using a small, clean gla.s.s rod--kept for the purpose--and never poured out of the bottle.

The oil cup should always have the cover on except when taking oil from it. Before it is refilled it should be very carefully cleaned.

The oiler should be perfectly clean, that kind which has a hexagonal nut on the handle and a gold tip being very excellent. Some careless workmen wipe the oiler on the back of the hand, on the clothes, on a dirty rag, on an old chamois, etc. The tip of the oiler should never touch the hand or fingers, as the acids in the perspiration are sure to cause a bad effect on the oil.

The following is a list of "oilers" which the author has seen used:--Peg wood, broom straw, quill, toothpick, match-stick, screw driver, tweezers, rat-tail file, piece of copper wire, horse-shoe nail, steel pen.