101 



Hsemacytometer. An apparatus for determining the number ol 



corpuscles in a given quantity of blood. [2, 20, 21, 22, 26.] 

 Haemacytometer, Barker's. An apparatus for counting and 



detecting blood corpuscules. [22.} 



Haemacytometer, Thoma's. A form of haemacytometer con- 

 sisting of a counting chamber in combination with an 



accurately calibrated mixing pipette for diluting the blood 



in a certain ratio. [2, 22, 26.] 

 Haemadromometer. An hsemadrometer. 

 Haematokrit. Part of a laboratory centrifuge (q.v.), usually 



rotated at about 10,000 revolutions per minute. [2, 22, 26.] 

 Haematometer. See Haemacytometer. [26.] 

 Haemodynamometer. An apparatus for measuring arterial and 



venous blood-pressure. [21, 26.] 

 Haemoglobinometer. An apparatus for the clinical estimation of 



haemoglobin in blood. [2, 21, 22, 26.] 

 Haemomanometer. A form of haemodynamometer. [26.] 

 Haemometer. A form of haemoglobinometer. 

 Haemoscope. An instrument for regulating and measuring the 



thickness of a layer of blood for spectroscopic observations. 



[26.] 



Hair Compass. See Hair Divider. [13, 15, 24, 27.] 

 Hair Divider. See Divider. [2, 5, 13, 15, 21. 24, 27,] 

 Hair Hygrograph. See Hygrograph. [2, 6, 15, 17.] 

 Hairspring Dividers. See Hair Divider. [2, 5, 13, 15, 21, 24, 27.] 

 Hall's Nautical Slide-Rule. See Slide-Rule. [15.] 

 Halometer. An instrument for measuring the forms and angles 



of salts and crystals ; a goniometer (q.v.). 

 Haloscope. An instrument for exhibiting phenomena connected 



with halos, parahelia, etc. 

 Hand Frame. A form of eyeglass which can be held in the 



hand. [2, 9, 15, 20.] 

 Hand Testing Thermometer. See Thermometer. [5, 6, 13, 15, 16, 



17, 21.] 

 Hanging Clinometer. See Clinometer. [6, 10, 15, 17, 21, 24, 25 



27.] 

 Hanging Compass. A form of compass very generally used in 



underground surveying. See Compass. [2. 13, 15, 16, 17, 



21, 27.] 

 Hanging Dial. A modification of the hanging compass for use 



in mining. [2, 6, 13, 15, 17, 21, 24, 27.] 



Hard Porcelain Ware. British make for laboratory work. [17.] 

 Harding's Engine Counter. An impioved form of engine revolu- 

 tion counter. See Counter. [5, 13, 15, 17, 28.] 

 Harmonic Analyser. An integrating machine for producing 



mechanically the harmonic constituents of meteorological, 



tidal, and other curves, to obviate calculations. 

 Harmonograph. An instrument by which Lissajou's and Mildi's 



figures may be drawn on paper by a pen. [19, 26.] 



