pyrophanous (pir of an us)

[ IMG:content-1383.png:[blocks in formation] the heat of his pottery and porcelain - kilns, and depended on the property of clay to con tract on exposure to heat. Many different modes have been pro A, pyrometer (Gauntlett's) the point posed er of dial d is turned by the unequal expansion of rods e, which are made fast at f: of three bra or copper rods surrounding one of iron which connects with dial through tube supported at g. B, pyrometer in which the motive power is a coil of wire inside e ', the connecting rods pa ing through tube h ' to dial at d'. pyrometer with screw-shaped metallic coil within the tube th which, when heated, moves the pointer of dial at e". tually employed for measuring high tempera tures: as (a) by contraction, as in Wedgwood's; ( b ) by the expansion of bars of different metals; (c) change of pre ure in confined gases, as in Lammy's i; by ment, or by the expansion of gases, as in the air-thermometer; (d) by the amount of heat imparted to a cold ma , as in Siemens's instrument; (c) by the fusing-point of solids; (f) by conduction and radiation of heat (see Pyroscope ); (9) by color, as red and white heat; (h) change in the velocity of sound; (i) by the resolution of chemical compounds;) by generation of electricity, as in Becquerel's thermo-electric pyrometer; and ( k ) by change in resistance to electricity, as in the instrument invented by Siemens, which may be adapted to measuring either high or low temperatures. pyrometric (pi-ro-met'rik), a. [As pyrometer + -ic.] Pertaining to the pyrometer, or to its use; ascertained or shown by means of the pyrometer. pyrometrical (pi-ro-met'ri-kal), a. [ metric + -al.] Same as pyrometric. pyrometrically (pi-ro-met'ri-kal-i), adv. In a pyrometric manner; with or by means of the use of the pyrometer. pyrometry (pi-rom'e-tri), n. [ pyromorphite (pi-ro-môr'fit), n. [So called in allusion to the peculiar crystalline form which a fused globule a umes on cooling; ore. pyro morpho us (pi-rō-môr'fus), a. [