Sherwood, Napoleon Bonaparte—Born in 1823. About 1855 he entered the watchmaking business in the employ of the Waltham Watch Co. He revolutionized jeweling methods and invented among other things a "Counter-sinker," "End-shake tools," "Truing-up tools" and "Opener." In 1864 he organized the Newark Watch Company but within a few months severed his connection with it. He died in 1872.
Sidereal Time—The standard used by astronomers; measured by the diurnal rotation of the earth, which turns on its axis in 23 hours, 56 minutes, 4.1 seconds. The sidereal day is therefore 3 minutes, 56 seconds shorter than the mean solar day. Mean time clocks can be regulated with greater facility by the stars than by the sun for the motion of the earth with regard to the fixed stars is uniform. Clocks all over the United States are so regulated from the Naval Observatory at Washington.
Side-Shake—Freedom of pivots to move sideways. See [End-Shake].
Slow Train—A train whose balance vibrates 14,400 times an hour. Now never used in pocket watches because of susceptibility to inequalities in the pull of the mainspring, jars, sudden movements, etc. Used, however, in marine chronometers.
Snail—A cam shaped like a snail, used generally for gradually lifting and suddenly discharging a lever, as in the striking mechanism of clocks.
Snailing—A method of ornamenting with circles and bars parts of a watch movement which it is not desirable to polish highly.
Solar Time—Time marked by the diurnal revolution of the earth with regard to the sun, of which the midday is the instant at which the sun appears at its greatest height above the horizon. This instant varies from twelve o'clock mean time because the earth also advances in its orbit and its meridians are not perpendicular to the ecliptic.
Spandrels—The corners of a square face outside the dial of a clock. Formerly very beautifully decorated. The age of the clock can be told approximately from the form of ornamentation employed.