National Geographic : 1920 Sep
__~t~F The Waltham Scientific Method for Eliminating Friction in the Escapement Which Means Accurate Time-keeping and Dependability of Your Watch THE pallet stones (pieces of selected Ruby or Sapphire perfectly formed in rectangular shape and highly polished) check the power which comes from the mainspring in your watch and then release it 18,000 times or beats per hour. The Riverside The most dependable moderate price watch in the world $75 and up In these governing func tions of the escape-wheel an impulse is given to the balance-wheel, which is transferred in governed movement, called Time, to the hands of the watch. Think, for a moment, of the possibility of friction, where the pallet jewels slide over the impulse sur face of the escape-wheel teeth (illustrated above) 432,000 timeseverytwenty four hours! Here was an opportunity for Waltham invention to minimize friction practi- WALTHAM THE WORLD'S WATCH OVER TIME "Mention The Geographic-It identifies you" cally to the vanishing point. And friction is the most insidious and dan gerous enemy to correct time-keeping in the works of a watch. After years of experiment and development, Waltham invented a machine equipped with a diamond cutter which not only cut the diameter of the escape-wheel to its exact size, but left the impulse surface of the teeth so perfectly shaped (rounded) and highly polished that when the face of the pallet stones jewelss) slid across that surface, friction was practically reduced to its ultimate minimum. It can readily be seen that this development of the diamond cutter has given the Waltham Watch a positive and valuable advantage in time-keeping and unvarying performance. The ordinary method of making an escape wheel is to polish with some polishing com pound, which being composed of gritty elements cannot be used without particles of grit becom ing embedded in the polished surface. This in time roughens the surface of the pallet stones, eventually causing greater friction and conse quent variability of time-keeping. The Waltham Scientific Method, then, of cut ting and polishing with a cutter made from a diamond is another hidden, yet vitally impor tant, superiority in the "works" of a Waltham Watch which provides an unanswerable reason why your watch selection should be a Waltham. This story is continued in a beautiful booklet in which you willfind a liberalwatch education. Sent ree upon request. Waltham Watch Company, Waltham, Mass.