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Astronomical Telescope. See Telescope. 



Astronomical Transit. See Transit. 



Astropatrotometer. An instrument to measure the brightness 



of stars by comparing them with a standard artificial star. 

 Astroscope. An old astronomical instrument formed of two 



cones on the surfaces of which the constellations were 



delineated. [18.] 

 Atmidometer. An instrument for measuring the evaporation 



of water, ice, and snow. [17, 21.] 

 Atmolyzer. An instrument for illustrating the separation of 



Atmometer. See Evaporometer. [17, 18.] 

 Atmospheric Slide-Rule. See Slide-Rule. (13, 15, 27.] 

 Atomizer. An instrument for reducing a liquid to the form of 



spray. 

 Atwood's Machine. An apparatus designed to demonstrate the 



relations of time and space in the motion of a falling body, 



used also to determine the value of the acceleration due to 



gravity. [18, 19.] 

 Audiometer. An instrument by which the power of hearing can 



be gauged or recorded on a scale. 

 Audiphone. An instrument, placed against the teeth, which 



conveys sound to the auditory nerve. 

 Auriscope. An instrument for examining, by means of an 



illuminating device, the condition of the ear. 

 Aurora Tube. A tube of uranium glass through which discharges 



of an induction coil are transmitted to produce the optical 



effect of aurora. [21.] 

 Ausculator. See Stethoscope. 

 Autoclave. A vessel under steam pressure, for sterilising and 



other purposes ; with a gauge for recording atmospheric 



pressure and temperature. [2, 26.] 

 Autoclave, Soxhlet's. An autoclave used in the determination 



of starch in grains and the diastatic power of malt. 

 Auto-Collimator. A telescope with a means of reflecting light 



through the instrument in the direction of the line of sight. 



[1, 3, 8, 17, 26, 27.] 

 Auto-Laryngoscope. An instrument by which one may inspect 



one's own larynx. [2.] 

 Automatic Machines. A term generally applied to machines 



which, when once set in action and provided with necessary 



motive power, continue to work without further human 



intervention. 

 Auto-Ophthalmoscope. An ophthalmoscope (q.v.) by which one 



may inspect one's own eyes. 



Auxanometer. A laboratory instrument to measure the rate of 

 growth of plants, usually fitted with clock-driven drum to 

 provide a record. 

 Auxanometer. Any instrument to measure the growth of plants. 



