(under subclass 323) Sight glasses provided with a guard or casing for protecting the glass or for catching the flying glass particles when the glass bursts.
SEE OR SEARCH THIS CLASS, SUBCLASS:
293, wherein are classified guards or casings having illuminating means incorporated therewith.
330, and 334, for the transparent closure plate type of gauge glasses which are usually provided with clamping means which project outward from the glass and in a sense form a guard.
