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Pyrometer, Radiation, F6ry. A pyrometer in which the radiant 

 heat from the body under test is f ocussed on a small thermo- 

 j unction, whose temperature is thus raised by an amount 

 depending on the temperature of the hot body. [4, 13, 21.} 



Pyrometer, Radiation, F6ry Spiral. In this instrument the 

 radiant heat is focussed by a bi-metallic spiral, the temper- 

 ature of the hot body being measured by the amount of 

 uncoiling of the spiral. [4, 13, 21.] 



Pyrometer, Recording. An instrument which automatically 

 records temperature on a chart. [4, 13, 16, 20, 21, 25, 26, 

 27.] 



Pyroscope. An instrument to measure the intensity of heat 

 radiating from a hot body, or the cooling effect of a cold 

 body. [4] 



Pyroscopes. See Seger Cones. [17.] 



Q.E.D. Chart-Holder. A device for holding a chart on the chart- 

 table. [28.] 



Q.E.D. Course-Corrector. An instrument of the Pelorus type 

 for indicating the true or magnetic course of a vessel and 

 measuring horizontal angles. [28.] 



Q.E.D. Rolling Role. An improved form of parallel rule for 

 chart work. [28.] 



Quadrant. An instrument for measuring altitudes, variously 

 constructed and mounted for specific uses in astronomy, 

 surveying, gunnery, etc. [2, 13, 15, 21, 27.] 



Quadrant, Gunner's. An instrument for determining the angle 

 of elevation of the gun. [13, 15.] 



Quadrant, Hartley's. A form of reflecting instrument invented 

 by John Hadley for taking angles. By this instrument the 

 observer sees at once the two objects both as touching the 

 same point though distant from each other almost to a semi- 

 circle. It is the original of the present form of sextant (q.v.). 

 [13, 15, 21.] 



Quadrantal Globes. The iron spheres used for the correction of 

 the quadrantal deviation on board steel ships. [15.] 



Quadhform Group Flashing Light. A form of lighthouse with 

 four sets of eight lenses with a light in the focus of each 

 set. [7] 



Quartz Lenses. Optically worked lenses made of rock crystal. 

 [2, 3, 10, 13, 14, 22, 26.] 



Quartz Plates. Rock crystal plates of specified thickness for 

 measuring retardation of polarised light. [2, 3, 10, 14, 20, 

 22, 26] 



Quartz Prisms. Optically worked prisms made of rock crystal. 

 [2, 3, 10, 13, 14, 26.] 



Quartz Spectrograph. See Spectrograph. [10, 14, 26.] 



Quartz Wedge. A wedge-shape plate of rock crystal used for 

 measuring retardation of polarised light. [2, 3, 10, 14, 20, 

 22, 26.] 



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