147 



Railway Gauge, Footner's. See Gauge. [15, 21, 27.] 



Rain- Gauge. An instrument for collecting and measuring the 

 rainfall. It consists essentially of a receiver, made of iron 

 or copper, usually of circular form, and of a graduated glass 

 measure accurately calibrated from the area of the receiving 

 surface of the gauge. [6, 13, 15, 17, 20, 25. 27.] 



Rain-Gauge, Balance Pattern. A rain-gauge with a balance 

 arrangement for automatically recording the rainfall. [6, 

 10, 13, 15, 17, 21.] 



Rain-Gauge, Float Pattern. Any rain-gauge indicating by means 

 of a float. [2, 5, 6, 10, 13, 15, 17, 21, 25, 27.] 



Rain-Gauge, Mountain. A form of rain-gauge with deep funnel 

 designed for use in very rainy localities and where the gauge 

 can be visited only at rare intervals. [6, 13, 15, 17, 20, 21, 

 24, 25, 26.] 



Rain-Gauge, Recording. A rain-gauge recording on a chart the 

 duration of and the total rainfall during a known period. 



Rain-Gauge, Tilting Bucket Pattern. A special form of self- 

 recording rain-gauge. [6, 10, 13, 15, 17, 21.] 



Rain-Gauge, Totalising. A rain-gauge recording total rainfall 

 on an outside dial. 115.] 



Ramsden Chain. A specially constructed steel chain devised by 

 Ramsden for Ordnance Survey work. Compound metal rods 

 are now used instead for this purpose. [8, 13.] 



Ramsden Eyepiece. See Eyepiece. [2, 3, 8, 10, 11, 13, 17, 18, 

 19, 20, 21, 22, 23, 24, 25, 26, 27.] 



Ramsey's Dividers. As devised by Sir W. Ramsey for dividing 

 tubes, scales, etc. 



Range-Finder. An optical instrument for finding the distance 

 of the observer from an object, as in gunnery, surveying, 

 etc. [2, 3, 6, 13, 15, 17, 18, 20, 21, 26, 27.] 



Range-Finder, H.S. A simple form of one man range-finder. 

 [5, 20.] 



Range-Finder, Weldon. A portable form of prismatic range- 

 finder. [5, 20.] 



Ranging Poles. See Picket Poles. [5, 13, 15, 16, 21, 26, 27.] 



Rapid Rectilinear Lens. See Lens. 



Rarefied Air Apparatus. An apparatus in which the effect of 

 the diminution of atmospheric pressure on living organisms 

 is observed. 



Rayleigh Synchronous Motor or Phonic Wheel. An instrument 

 for determining the absolute periodicity of large tuning 

 forks and of alternating electric currents, and for time- 

 recording experiments. [19] 



Reading-Glass. A large magnifying lens with a handle, used to 

 assist in reading, etc. [2, 5, 8, 9, 13, 15, 16, 17, 20, 21, 24, 

 26. 27, 28] 



Reading Telescope. See Telescope. [1, 2, 3, 10, 13, 15 1 17, 19, 

 21, 26, 27.] 



