HYALONEMA n.
genus of hexactinelline sponges, having a long stem composed of very long, slender, transparent, siliceous fibres twisted together like the strands of a color. The stem of the Japanese species (H. Sieboldii), called glass-rope, has long been in use as an ornament. See Glass-rope.
IMPEDANCE n.
The apparent resistance in an electric circuit to the flow of an alternating current, analogous to the actual electrical resistance to a direct current, being the ratio of electromotive force to the current. It is equal to R2 + X2, where R = ohmic resistance, X = reactance. For an inductive circuit, X = 2pfL, where f =…