Microlepidoptera
(||Mi`cro*lep`i*dop"te*ra) n. pl. [NL. See Micro-, and Lepidoptera.] (Zoöl.) A tribe of
Lepidoptera, including a vast number of minute species, as the plume moth, clothes moth, etc.
Microlestes
(||Mi`cro*les"tes) n. [NL., from Gr. mikro`s small + a robber.] (Paleon.) An extinct genus
of small Triassic mammals, the oldest yet found in European strata.
Microlite
(Mi"cro*lite) n. [Micro- + -lite.] (Min.)
1. A rare mineral of resinous luster and high specific gravity. It is a tantalate of calcium, and occurs in
octahedral crystals usually very minute.
2. (Min.) A minute inclosed crystal, often observed when minerals or rocks are examined in thin sections
under the microscope.
Microlith
(Mi"cro*lith) n. [Micro- + lith.] (Min.) Same as Microlite, 2.
Microlithic
(Mi`cro*lith"ic) a. Formed of small stones.
Micrologic
(Mi`cro*log"ic Mi`cro*log"ic*al) a. Of or pertaining to micrology; very minute; as, micrologic
examination. — Mi`cro*log"ic*al*ly, adv.
Micrology
(Mi*crol"o*gy) n. [Micro- + -logy.]
1. That part of science which treats of microscopic objects, or depends on microscopic observation.
2. Attention to petty items or differences. W. Taylor.
Micromere
(Mi"cro*mere) n. [Micro- + -mere.] (Biol.) One of the smaller cells, or blastomeres, resulting
from the complete segmentation of a telolecithal ovum.
Micrometer
(Mi*crom"e*ter) n. [Micro- + -meter: cf. F. micromètre.] An instrument, used with a telescope
or microscope, for measuring minute distances, or the apparent diameters of objects which subtend
minute angles. The measurement given directly is that 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 or outer periphery of the ring. — Double image micrometer,
a micrometer in which two images of an object are formed in the field, usually by the two halves of a
bisected lens which are movable along their line of section by a screw, and distances are determined by
the number of screw revolutions necessary to bring the points to be measured into optical coincidence.
When the two images are formed by a bisected object glass, it is called a divided-object-glass micrometer,
and when the instrument is large and equatorially mounted, it is known as a heliometer. — Double
refraction micrometer, a species of double image micrometer, in which the two images are formed by
the double refraction of rock crystal. — Filar, or Bifilar, micrometer. See under Bifilar. — Micrometer
caliper or gauge (Mech.), a caliper or gauge with a micrometer screw, for measuring dimensions with
great accuracy. — Micrometer head, the head of a micrometer screw. — Micrometer microscope,
a compound microscope combined with a filar micrometer, used chiefly for reading and subdividing the
divisions of large astronomical and geodetical instruments. — Micrometer screw, a screw with a graduated
head used in some forms of micrometers. — Position micrometer. See under Position. — Scale,
or Linear, micrometer, a minute and very delicately graduated scale of equal parts used in the field
of a telescope or microscope, for measuring distances by direct comparison.
Micrometric
(Mi`cro*met"ric Mi`cro*met"ric*al) a. [Cf. F. micrométrique.] Belonging to micrometry; made
by the micrometer. — Mi`cro*met"ric*al*ly, adv.
