7 6 



Conductometer. An instrument for illustrating the comparative 

 power of different substances for conducting heat, electricity, 

 etc. 



Confectioners' Thermometer. See Thermometer. [5, 6, 13, 15, 

 16, 17, 20, 21.} 



Constant Deviation Prism. See Prism. [3, 10, 13, 14.] 



Constant Temperature Apparatus. Any apparatus for main- 

 taining a constant temperature in an enclosed space. See 

 Thermostat. 



Contact Makers. See Mine-Explosions Apparatus. Operated by 

 the explosion and connected with the sampling bottles so 

 as to determine the instant at which the sample of gas 

 should be taken. [4.] 



Co-ordinate Comparator. See Comparator. {4.} 



Co-ordinatograph. An instrument for plotting points by their 

 rectangular co-ordinates. 



Copper Case Thermometers. See Thermometer. [13, 15, 16, 17, 

 20, 21, 27, 28.1 



Copying Glass. An arrangement of glass plate and reflecting 

 mirror beneath ; used in tracing drawings and plans. [20, 

 24, 27.} 



Cordite Apparatus. An apparatus for estimating the volatile 

 matter in gun-cotton. 



C0 2 Recorder. An instrument for determining and recording 

 the percentage of carbon dioxide in the gases emitted by a 

 chimney, etc. [4, 13, 17.] 



C0 2 Recorder, Bi-Meter. A type of CO 8 recorder in which the 

 flue gases are measured in gas meters before and after the 

 absorption of the CO 8 by lime or similar agent, the two 

 meters being connected by a differential gearing to the 

 mechanism driving the recording pen. [4.] 



Corner Cube Prism. A prism having three triangular surfaces at 

 right angles to each other and one surface at equal inclina- 

 tion to the other three. It has the property of reflecting 

 light incident at any angle on the large surface back along 

 the line of incidence. [3, 6, 10, 13, 14.} 



Corner Curve. A drawing curve used by draughtsmen. [2, 15, 

 20, 21, 24, 25, 27.] 



Coronet Compass-Card. See Compass-Card. [13, 15, 16, 28.] 



Corundum. A hard crystal used for the pivots and caps of 

 magnetic compasses, etc. [8, 16.] 



Cosmolabe. An instrument resembling the astrolabe (q.v.), 

 formerly used for measuring the angles between heavenly 

 bodies. 



Cosmosphere. An apparatus for showing the position of the 

 earth at any given time, with reference to that of the fixed 

 stars. A hollow glass globe, upon which are depicted con- 

 stellations ; terrestrial sphere inside. [13.] 



