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at of the image of the object formed at the focus of the object glass. Circular, or Ring, micrometer, a metallic ring fixed in the focus of the object glass of a telescope, and used to determine differences of right ascension and declination between stars by observations of the times at which the stars cross the inner…

A very sensitive modification or application of the thermopile, used for indicating minute changes of radiant heat, or temperature.

ded; involving the use of two threads; as, bifilar suspension; a bifilar balance. Bifilar micrometer (often called a bifilar), an instrument form measuring minute distances or angles by means of two very minute threads (usually spider lines), one of which, at least, is movable; -- more commonly called a filar micromete…

fifteen yards. Beck. Draper's Dict. Such a proud piece of cobweb lawn. Beau. & Fl. Cobweb micrometer, a micrometer in which threads of cobwed are substituted for wires.

The notched scale of a wire micrometer.

t for determining the magnifying power of telescopes, consisting usually of a doubleimage micrometer applied to the eye end of a telescope for measuring accurately the diameter of the image of the object glass there formed; which measurement, compared with the actual diameter of the glass, gives the magnifying power.…

racterized by threads stretched across the field of view; as, a filar microscope; a filar micrometer.

A micrometer. [R.] Knight.

Belonging to micrometry; made by the micrometer. -- Mi`cro*met"ric*al*ly, adv.

The art of measuring with a micrometer.

uick movements. -- Position finder (Mil.), a range finder. See under Range. -- Position micrometer, a micrometer applied to the tube of an astronomical telescope for measuring angles of position in the field of view. -- Single position (Arith.), the method of solving problems, in which the result obtained by operati…

lines seems to meet and interlace with another set in a different plane. -- Reticulated micrometer, a micrometer for an optical instrument, consisting of a reticule in the focus of an eyepiece. -- Reticulated work (Masonry), work constructed with diamond-shaped stones, or square stones placed diagonally.…

d of mail made of small steel rings sewed upon a garment of leather or of cloth. -- Ring micrometer. (Astron.) See Circular micrometer, under Micrometer. -- Saturn's rings. See Saturn. -- Ring ousel. (Zoöl.) See Ousel. -- Ring parrot (Zoöl.), any one of several species of Old World parrakeets having a red ring arou…

between the teeth of the wheel; -- called also a worm. -- Lag screw. See under Lag. -- Micrometer screw, a screw with fine threads, used for the measurement of very small spaces. -- Right and left screw, a screw having threads upon the opposite ends which wind in opposite directions. -- Screw alley. See Shaft alle…

of a circle, used for measuring differences of declination too great for the compass of a micrometer. When it is used for measuring zenith distances of stars, it is called a zenith sector. Dip sector, an instrument used for measuring the dip of the horizon. -- Sector of a sphere, or Spherical sector, the solid generat…

r. -- Stage lights, the lights by which the stage in a theater is illuminated. -- Stage micrometer, a graduated device applied to the stage of a microscope for measuring the size of an object. -- Stage wagon, a wagon which runs between two places for conveying passengers or goods. -- Stage whisper, a loud whisper,…

ent used for measuring the distance of an object from an observer; as, a telescope with a micrometer for measuring the apparent diameter of an object whose real dimensions are known.

f wooden lathing for holding plastering. -- Wire mattress. See Wire bed, above. -- Wire micrometer, a micrometer having spider lines, or fine wires, across the field of the instrument. -- Wire nail, a nail formed of a piece of wire which is headed and pointed. -- Wire netting, a texture of woven wire coarser than o…

ed vertical semicircle, and a level for setting it to a given zenith distance, and with a micrometer for measuring the difference of the zenith distances of the two stars.