85 



Dynamometer Car Equipment. A special set of instruments 

 designed and arranged for use in the dynamometer car 

 to record the various quantities required in testing speed 

 and work on a railway train whilst in motion. [4] 



Dynamometer, Thrust and Torque. A dynamometer for 

 measuring the thrust and torque of shafts of aeroplane 

 propellers. [4, 16.] 



Ear-Trumpet. An instrument designed for the -collection and 

 conduction of sound-waves ; for the use of the deaf. 



Ebuliscope. An instrument for observing the boiling point of 

 liquids, especially for determining the alcoholic strength of 

 a mixture by the temperature at which it boils. 



Eccentrolineads. An instrument for drawing eccentric lines, 

 arms of wheels, etc. [6, 21, 27.] 



Echelon Grating. A grating for the production of spectra, 

 composed of a flight of steps of plane-parallel glass plates of 

 equal thickness placed in echelon. [10, 14, 26.] 



Echometer. A graduated scale for measuring the duration of 

 sounds and determining their different values and the 

 relation of their intervals. 



Echoscope. An instrument for intensifying sounds produced by 

 percussion of the thorax. 



Eclipsareon. An old instrument for showing the phenomena of 

 eclipses ; as to their time, quantity, duration, progress. [20.] 



Economiser Thermometer. See Thermometer. [5, 6, 13, 16, 21.] 



Edgeworth's Stadiometer. See Stadiometer. [13.] 



Edney's Air-Pressure Gauge. See Gauge. [5] 



Ehrlich Eyepiece. See Eyepiece. [2, 3, 22, 26] 



Eidograph. An instrument for copying drawings on the same 

 or different scales ; a form of pantograph (q.v.). [2, 5, 13, 

 15, 17, 20, 21, 21, 25, 27] 



Eidoscope. An instrument on the principle of the kaleidoscope 

 which produces an infinite variety of geometrical figures 

 by the independent revolution of two perforated metallic 

 discs on their axes. [13.] 



Eight-Bell Clock. A timepiece with a special striking arrange- 

 ment, which, instead of striking the hour from i to 12, 

 strikes on a gong or bell, to indicate the tune according 

 to the ship's watches as kept at sea, striking consecutively 

 from i to 8 in every 4 hours. Some are also made to strike 

 from i to 8, then i to 4, twice over consecutively, to indicate 

 the dog watches, and i to 8 again. [13, 15, 16, 17, 28.] 



Eikonometer (Wright's). An optical apparatus for determining 

 the magnifying power of a microscope or for the measurement 

 of microscopic objects. The image is brought to a focus on 

 a micrometer scale which is examined by a magnifier. [3, 

 22, 26.] 



Einthoven String Galvanometer. See Galvanometer. [4.] 



