FILTER n. 2 definitions
on; a chamber or device containing such 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 san…
PETROLATUM n.
without taste or odor, derived from petroleum by distilling off the lighter portions and purifying the residue. It is a yellowish, fatlike mass, transparent in thin layers, and somewhat fluorescent. It is used as a bland protective dressing, and as a substitute for fatty materials in ointments. U. S. Pharm.…