FILTER n.
substance; a strainer; also, a similar device for purifying air. Filter bed, a pond, the bottom of which is a filter composed of sand gravel. -- Filter gallery, an underground gallery or tunnel, alongside of a stream, to collect the water that filters through the intervening sand and gravel; -- called also infiltrati…
FLASK n.
ore parts; viz., the cope or top; sometimes, the cheeks, or middle part; and the drag, or bottom part. When there are one or more cheeks, the flask is called a three part flask, four part flask, etc. Erlenmeyer flask, a thin glass flask, flat-bottomed and cone-shaped to allow of safely shaking its contents laterally wi…
FORCING n.
or pit, a plant bed having an under layer of fermenting manure, the fermentation yielding bottom heat for forcing plants; a hotbed. -- Forcing engine, a fire engine. -- Forcing fit (Mech.), a tight fit, as of one part into a hole in another part, which makes it necessary to use considerable force in putting the two p…