[机] 胶粘板岩, 胶粘石板

Slate \Slate\ (sl[=a]t), n. [OE. slat, sclat, OF. esclat a
shiver, splinter, F. ['e]clat, fr. OF. esclater to shiver, to
chip, F. ['e]clater, fr. OHG. sleizen to tear, slit, split,
fr. sl[=i]zan to slit, G. schleissen. See {Slit}, v. t., and
cf. {Eclat}.]
1. (Min.) An argillaceous rock which readily splits into thin
plates; argillite; argillaceous schist.

2. Any rock or stone having a slaty structure.

3. A prepared piece of such stone. Especially:
(a) A thin, flat piece, for roofing or covering houses,
etc.
(b) A tablet for writing upon.

4. An artificial material, resembling slate, and used for the
above purposes.

5. A thin plate of any material; a flake. [Obs.]

6. (Politics) A list of candidates, prepared for nomination
or for election; a list of candidates, or a programme of
action, devised beforehand. [Cant, U.S.] --Bartlett.

{Adhesive slate} (Min.), a kind of slate of a greenish gray
color, which absorbs water rapidly, and adheres to the
tongue; whence the name.

{Aluminous slate}, or {Alum slate} (Min.), a kind of slate
containing sulphate of alumina, -- used in the manufacture
of alum.

{Bituminous slate} (Min.), a soft species of sectile clay
slate, impregnated with bitumen.

{Hornblende slate} (Min.), a slaty rock, consisting
essentially of hornblende and feldspar, useful for
flagging on account of its toughness.

{Slate ax} or {Slate axe}, a mattock with an ax end, used in
shaping slates for roofs, and making holes in them for the
nails.

{Slate clay} (Geol.), an indurated clay, forming one of the
alternating beds of the coal measures, consisting of an
infusible compound of alumina and silica, and often used
for making fire bricks. --Tomlinson.

{Slate globe}, a globe the surface of which is made of an
artificial slatelike material.

{Slate pencil}, a pencil of slate, or of soapstone, used for
writing on a slate.

{Slate rocks} (Min.), rocks which split into thin lamin[ae],
not necessarily parallel to the stratification; foliated
rocks.

{Slate spar} (Min.), a variety of calcite of silvery white
luster and of a slaty structure.

{Transparent slate}, a plate of translucent material, as
ground glass, upon which a copy of a picture, placed
beneath it, can be made by tracing.