16-Size 14K Yellow-Gold 19-Jewel Adjusted to 5-Positions Railroad Grade Waltham Riverside Pocket Watch
U.S./Mass.; Waltham; Type; Man’s; SN#15,133,218; CA1906
CASE: The 14K yellow-gold No. 5,218,313 16-size open face case displays a monogram on the back, 90 grams (TW)
DIAL: This white porcelain double sunk dial features subsidiary seconds dial, black Arabic hour numerals, red 5-minute Arabic numerals, spade hands and is signed “Waltham.”
MOVT: The 19-jewel stem-set No. 15,133,218 nickel movement has a lever escapement, bridge-style layout and is signed.
C 3 (Case is in Very Good Condition)
D 3-43 (The Dial is in Very Good Condition – faint hairline)
M 2 (The Movement is in Perfect Condition)
R 8 (Rarity based on a scale of #1 being very common to #10 being extremely rare)
Expert’s Opinion: A heavy 14K gold case and an excellent high-grade movement!  AI-CAT180-14 Adjustment - Watch adjustment is the process of correcting those errors in the watch that cause variation in time keeping. These include temperature influences, variation in driving power and position of the watch with respect to mechanism such as pendant up or dial up.Watches with better calibre movements will have been adjusted at the factory for a number of positions. The usual array of positions include a subset of the following positions:
1. Dial up 2. Dial down 3. Bow up 4. Bow down (Not required by Railroad) 5. Bow left 6. Bow rightThese positional adjustments are intended to insure that the watch is just as realiable and accurate regardless of the position in which it is stored or used.In addition to positional adjustments, the watch may also be adjusted for Temperature(heat/cold). Temperature affects different elements in different ways. Heat will cause some metals to expand faster than others, and cold may cause some metals to contract more than others. A watch that is adjusted to temperatures will usually include some combination of metals that allow the watch to maintain its proper functionality within a larger range of temperatures than one that is not adjusted for temperature.Another type of adjustment is Isochronism. As a typical watch spring unwinds the pressure it exerts on the wheels of the movement reduces. This has the potential to create a difference in the operating speed of a fully wound watch versus the same watch in an nearly fully unwound state. Adjustments for isochronism attempt to compensate for this potential by maintaining the same pressure from the spring throughout most of the operating range of the watch. This sort of adjustment was generally seen only on the finest railroad grade watches of the 20th century.The general rule of thumb with adjustments is that more is better. However, for average every day use, a typical unadjusted watch was perfectly adequate. Stem Wind/Stem Set Movement
Stem-wind, stem-set movements did away with the watch key which was a necessity for the operation of any pocket watch up to that point. The crown of the watch is pulled out a short distance allowing the hands to be turned to set the watch.  The crown is pressed back into place and is turned to wind the watch. Lever Escapement
An escapement is a device in mechanical watches and clocks that transfers energy to the timekeeping element (the "impulse action") and allows the number of its oscillations to be counted (the "locking action"). The impulse action transfers energy to the clock's timekeeping element (usually a pendulum or balance wheel) to replace the energy lost to friction during its cycle and keep the timekeeper oscillating. The escapement is driven by force from a coiled spring or a suspended weight, transmitted through the timepiece's gear train. Each swing of the pendulum or balance wheel releases a tooth of the escapement's escape wheel gear, allowing the clock's gear train to advance or "escape" by a fixed amount. This regular periodic advancement moves the clock's hands forward at a steady rate. At the same time the tooth gives the timekeeping element a push, before another tooth catches on the escapement's pallet, returning the escapement to its "locked" state. The sudden stopping of the escapement's tooth is what generates the characteristic "ticking" sound heard in operating mechanical clocks and watches. Bridge Style Layout
The metal bar which bears the pivot of wheel and is supported at both ends.  The bridge style watch has two or three fingers to hold the wheels in place and together are called a bridge.  The term bridge (horologically) is one that is anchored at both ends.