53 



Aeroplane Speed Indicator. See Indicator. [4, 9, 15, 17.] 

 Aeroplane Speedometer. See Speedometer. [9, 15.] 

 Aerorthometer. An instrument for use at gas-testing stations. 



[21.] 

 Aeroscope. An instrument for collecting spores, germs, and 



bacteria from the air. 

 Aesthesiometer. An instrument to determine at how short a 



distance two impressions on the skin can be distinguished, 



generally consisting of two pricking instruments whose 



distance apart can be varied and measured. [8.] 

 Aethrioscope. An instrument to determine the radiation of the 



sky. [17, 21.] 

 Agate. (i) A pivot of a mariner's compass, a knife-edge or 



plane for balance, etc. (2) A tool made of agate for 



burnishing. [13, 15, 16, 26, 27.] 

 Agate Cap. A metal cap with an agate setting used as the pivot 



in magnetic compasses. [13, 15, 16, 21, 24, 26, 27, 28.] 

 Ahrens Prism. See Prism. [2, 3, 22, 26.] 

 Aim Corrector. An instrument used to correct the sighting and 



elevation of a gun when being fired. [13, 15.] 

 Aim Teacher. A device to facilitate the instruction of recruits 



in laying a rifle correctly. 

 Air Condenser. See Air Pump. 

 Air Meter. An instrument for measuring the velocity of air 



currents for testing ventilation or draught of furnace flues, 



etc. See Anemometer and Air Gauge. [4, 5, 6, 13, 16, 17, 



20, 21, 24, 27.] 

 Air Poise. An instrument for measuring the weight of the 



atmosphere. See also Barometer. [13, 16.] 

 Air Pressure Gauge. See Gauge. [5, 15, 16, 17, 21.] 

 Air Pressure Gauge (Admiralty pattern). See Gauge. [5, 15, 16, 



17, 21.] 



Air Pressure Gauge, Self-recording. See Gauge. [5.] 

 Air Pump. Any form of pump used for the compression or 



exhaustion of the air or other gas in an enclosed space. 



[2, 6, 17, 21.] 



Air Pump, Bianchi's. A double action air pump. 

 Air-Speed Indicator. See Speedometer. [5, 6, 13, 15, 17.] 

 Airship Manometer. See Manometer. [13, 15.] 

 Air Thermometer. See Thermometer. [13, 19, 21.] 

 Air Tube. See Draught Gauge. [4, 16, 17.] 

 Aitken's Dust Counter. See Dust Counter. 

 Alarm Thermometer. See Thermometer. [4, 6, 13 16, 17, 24, 15.] 

 Albumenometer. Any instrument for determining the parts per 



1,000 of albumen in urine. [13, 21.] 

 Albumenometer, Auirecht's. 

 Albumenometer, Esbach's. [21.] 

 Albuminimeter. See Albumenometer. [21.] 



