If dust be on the bench paper, or in the movement tray, the pivots will surely transfer some of it to the bearings when the wheels are being put to place.

The scape-wheel, mainspring and other parts, the rubbing surfaces of which may come in contact with the fingers, should be so handled as to allow no perspiration to become deposited on any surface which may afterwards require oiling, as the acids contained in the perspiration will exert an injurious effect on the oil.

The owners of watches sometimes subject them to very hard treatment by using perfumes, etc., and then some people perspire more than others, while the perspiration of some persons contains more acids, or is more rancid, than that of others. For these reasons the method of testing oil by putting it on watches kept to loan to customers as Saunier recommends cannot be relied on.

Oils should be kept in a clean, cool, dark place. The wrapper or label on the bottle should be dark blue or black, to exclude all light, as, if this is not done, the oil will be more liable to decomposition, except in the case of a mineral oil, which is not affected by light. All vegetable and animal oil which has been "bleached" by exposure to the light is more liable to decomposition on exposure to air than that which is unbleached.

~88. The Effect of Age on Oils.~ Writing on this subject Mr. Henry G.

Abbott[28] states as follows: "There is a popular fallacy existing in the trade that oils should be used when fresh, and even that acknowledged authority, Saunier, says, "do not buy from motives of economy bottles that have laid for years in the shop." This may be true and probably is in regard to animal and vegetable oils, which are likely to become rancid if kept for a long time, but William F. Nye, one of the largest and most celebrated manufacturers of fine watch and chronometer oils in the world, declares that blackfish oils are improved by age, and his oils are seldom placed on the market in the same year as obtained.

We are indebted to the same authority for the statement that oils of this kind are clearer and more brilliant after some years than fresh oils." Though Mr. Abbott has made some very valuable additions to the literature of the profession, the author begs permission to call attention, in reference to this, to the following facts:

Mr. Abbott says that vegetable and _animal_ oils are likely to become rancid if kept for a long time, but _blackfish_ oils are not. Brant[29]

states that the porpoise or _Phocoena communis_, Cuv., and the blackfish, or _Phocoena globiceps_, are of the subdivision _Delphinodea_, or dolphins, of the family of _Cetacea_, or whales, an order of the vertebrated mammiferous marine _animals_. Adler Wright[30]

states that "the term "train oil," strictly speaking, applies to any oil extracted from the blubber of cetaceans and the allied marine mammalia, such as the seal, porpoise, dolphin and walrus." Huxley cla.s.ses among cetacea the dolphins, porpoises, grampus and narwhal. Authorities might be quoted _ad infinitum_ to show, not only that porpoise-jaw oil and blackfish-melon oil _are animal oils_, but that they possess properties similar to other animal oils as far as their liability to decompose by age, more or less, is concerned.

Furthermore, Thurston[31] states that "all vegetable and animal oils are compounds of glycerine and the fatty acids. When they become old decomposition takes place, and acid is set free, by which action, as is commonly said, the oils become rancid." Thus Saunier is borne out in his admonition.

~89. In Conclusion~, the author wishes to state, that as he has been able to find but little in the literature of the craft in English, French or German, he has pursued the study of the "properties and relative values of lubricants in horology" upon lines which have suggested themselves as being best adapted to give good results. As much that is herein contained is new and original in its application in horology, the theories advanced may be in some respects incorrect. The tests of various oils have, no doubt, been subject to personal error; but it has been the earnest desire of the author to give the subject the attention it deserves.

In order that truth may prevail and that justice may be done to the various manufacturers of oils, as well as to the author and his subject, he will again request criticism through the trade press in any matter in which he may seem to be at fault. He further wishes that others may become interested, and that the makers and repairers of watches, chronometers and clocks, as well as the manufacturers of oil, will further a.s.sist in these investigations by making similar or other experiments, and report the result of the same through the trade press in order that this very important subject may be thoroughly understood.

In furtherance of this object the author will furnish samples of oils _free_ to anyone wishing to make experimental tests of _any_ kind, on condition that the results of such tests shall be published or communicated to the author for future publication. Address, W. T. Lewis, President Philadelphia Horological Society, Philadelphia, Pa.

FOOTNOTES:

[12] Thurston. Friction and Lost Work in Machinery.

[13] As the fish from which these oils are obtained are of the mammalia order, their oils are cla.s.sed among the animal oils.

[14] The Horological Journal, Apr., 1881. Vol. xxiii. Page 98.

[15] Pharmacopoea Germanica. 1882.

[16] The National Dispensatory. 1884.

[17] Saunier, Watchmaker"s Hand-Book, p. 104, Eng. Edition; p. 129, Am.

Edition.

[18] Brannt. Animal and Vegetable Fats and Oils.

[19] Paper read in the Chemical Section, British a.s.sociation, Plymouth Meeting, 1879.

[20] Swansea Meeting. British a.s.sociation, 1880.

[21] This work is compiled from a course of lectures delivered by the author before the Philadelphia Horological Society, 1896.

[22] Thurston. Friction and Lost Work in Machinery.

[23] Proceedings N. E. Cotton Manufacturers" a.s.sociation, Nov. 28, 1880.

[24] The average teaspoon holds 5 cubic centimeters.

[25] 1 millimeter = .039 + inch.

[26] Thurston. Friction and Lost Work in Machinery.

[27] This work is compiled from a series of papers read and lectures delivered by the author before the Philadelphia Horological Society, 1896.

[28] Abbott. The American Watchmaker and Jeweler, 1892, page 249.

[29] Brant. Animal and Vegetable Fats and Oils, pages 297-299.

[30] Adler Wright. Oils, Fats and Waxes, and Their Manufactured Products, p. 292-293.

[31] "Friction and Lost Work in Machinery."