SAFETY n.
of steam, or confined gas, water, etc., from a boiler, or other vessel, when the pressure becomes too great for safety; also, sometimes, a similar valve opening inward to admit air to a vessel in which the pressure is less than that of the atmosphere, to prevent collapse.
SCALE n.
ll hemipterous insects belonging to the family Coccidæ, in which the females, when adult, become more or less scalelike in form. They are found upon the leaves and twigs of various trees and shrubs, and often do great damage to fruit trees. See Orange scale,under Orange. -- Scale moss (Bot.), any leafy-stemmed moss of…