Rensselaer Republican, Volume 20, Number 6, Rensselaer, Jasper County, 13 October 1887 — Jewels for watches. [ARTICLE]

Jewels for watches.

1 An Interesting Article on the Const ruction of Time Pieces. u RelnacVe InJawelry Hews. It is surprising that while most points, i scientific, technical, or otherwise, appertaining to the construction of watches, etc., have received an exhaustive consideration, the matter of jewels ! for the purpose of pallets in our lever , watches having been only superficially treated. To obviate the use of oil on ! escapements, or to reduce the necessity of its use and io be choice in its selection, have been matters well considered, and the excellence of the spriifg detent or the chronometer escapement on accouht of its ability to dispense with the use of oil is well known and appreciated; vet there should be a difference and an | advantage in the choice of jewels on account of their contact with oil under different conditions has to my knowledge never been discussed in print, anil, as the subject lias in my opinion points, I will venture to give my ideas on the subject. That .the lever escapement is the best for watches or time pieces submitted to rough visage®, is generally admitted. Its only drawback is the necessity of oil on the friction or impulse faces. A i noted watchmaker of London lias in lau-r years assumed, that by changing the proportions pf the escapement in various details, the lever escapement might be successfully employed in ship chronometers, and he has scent some chronometers with his ideal escapements to the Greenwich Observatory for trial. But to my sincere regret, I eee by the first published results of the competitive trials at . Greenwich, That one of these chronometers stands at the bottom of the list. It would be rash to assume that the escapement is the cause of this failure, but it is e’qualTy' unfortunate to think that the experiment should not have proved at suc-cess-more particularly, as I believe, that his first venture had a like result. I have long come to the conclusion thatdifferent jewels act very differently n contact with oil, though the causes thereof were not easily ascertained. The points to be considered were the quality of the oil, the metal the escape wheel was made of, and the jewel. I will first consider' the je wel. There was a time when watchmakers made lever watches with ratchet escape wheels made of steel; they were soon abandoned. These ratchet teeth escape wheels made of steel would lose their points by corrosion in a very short time in contact with ruby or garnet pallets, but I have seen watches where thtse | escape wheels worked well and successfully in contact with sapphire pallets. Swiss duplex watches with steel escape wheels were made, and the pointed or horizontal teeth would often act on a ruby roller, and the result would be the same with these duplex wheels as with the steel ratchet escape wheels in English watches; a rusty corrosion would destroy the points of the teeth. While these pointed teeth stee. wheels will not work well with rubies, etc., club tooth "Steel escaue wheels do veyy wcll apparently, but these will cut the rubies if they aie high colored. Though this fact is well known our Swiss friends still continue to use them for purely commercial reasons, for they look so attractive. Commercial reasons make the watch manufacturer do many things which are technically wrong, and which he knows to be wrong, but the watches sell and the sale is profitable. The difference between tlie effect on the ratchet tooth steel escape wheel and on the club tooth steeT escape wheel deserves attention, b».t not at present. Brass escape wheels in contact with garnet pallets act similarly as steel wheels in contact with ruby pa lets. The ratchet tooth escape wheel suffers abrasion at itß points, while the American club tooth wheel is apt to pit the garnets at the locking faces, particularly if there is much drop. Enough has been said to demonstrate the fact that the particular kind of iewel used for pallets in a lever watch may lave an influence on its rate, and that the selection of jewels for this purpose is of some moment. It would be extremely difficult, if not impossible, to give the chemical reasons why these different jewels act differently under the same circumstances; all we can expect to do is to observe closely and benefit bv our experience. This much we may safely assert, that the coloring substance contained in the constituents of the jewels have something to do with it. / For chemists have told us that the basis of the colored gems composing tlie ruby' and emarnld groups is alumnia, eiystaliz'ed alumnia in corundum, hyaline corundum in the j case of the ruby and the sapphire. The •onstitnents of the ruby and the sapphire | is then the same, save the' coloring substance. The coloring matter in the oriental ruby is said to be iron rust or ixide of iron; the coloring matter in the sapphire is said to be oxide of chromium. But chromium forms* combinations readily with numerous and is one of the principal agents for impartingthe beantif ill .hues to. porcelain, and it may be, therefore, extremely"difficult) even for a chemist, to determine in j what com bination chromium imparts j the. different shades of color to The ; sapphire,- As far as mv experience goes. the pale but distinct bine sapphire is the j best for pallets. These coloring matters may give these jewels a greasy, jlippery

surface, or a harsh and grating one, as would seem to be the case in the high colored ruby. I have been told that the bloodstone is of a greasy nature, and •though soft, is highly recommended for j pallets in largs clocks, needing very little or no oil at all. A prominent Swiss watch deceased, used to employ sapphire pallets of the color mentioned, and my experience with of these watcheß has impressed me very strpngly with their unequalled steady rate. Ji I have succeeded in the foregoing in calling the attention of those whose earnest endeavor ten is to the perfection >,of our lever watch, and if I have demonstrated that there is a choice in pallet stones in relation to the use of oil on pallets, I have attained the object of mv effort.