n 9 



Marching Compass. See Compass. [2, 5, 6, 10, 13, 15, 16, 17, 



20, 21, 24, 25, 26, 27.] 



Marconi Telegraph. The term usually applied to the wireless 

 telegraph apparatus named after its principal inventor. 



Mareograph. A registering tide-gauge. [15, 17, 21.] 



Marey's Sphygmograph. See Sphygmograph. 



Marine Barometer. See Barometer. [5, 6, 13, 15, 16, 17, 21, 

 26, 28.] 



Marine Chronometers. See Chronometers. [13, 15, 16, 17, 20, 



21, 24, 28.] 



Mariner's Compass. A ship's compass (q.v.). [9, 13, 15, 16, 17, 

 20, 21, 28.] 



Mark VI. Compass. A Service pattern marching compass. [6, 

 9, 13, 15, 16, 20, 21, 24, 25, 26, 27.] 



Mark VII. Compass. A Service pattern marching compass. [6, 

 9, 13, 15, 16, 20, 21, 24, 25, 26, 27.] 



Mark Vin. Compass. A Service pattern marching compass, [fl, 

 9, 13, 15, 16, 21, 25, 26, 27.] 



Mark IV. Telescope. A Service pattern signalling telescope (q.v.). 



Marking Gauge. A tool or instrument for rapidly marking set 

 dimensions on woodwork, etc. [8, 15.] 



Marquois Scale. A special scale and triangle used for military 

 drawing. [2, 5, 6, 13, 15, 17, 20, 21, 24, 25, 26, 27.] 



Mason's Hygrometer. A form of wet and dry bulb thermometer. 

 [5, 6, 9, 13, 15, 16, 17, 20, 21, 24, 26.] 



Mathematical Instruments. The various instruments used by 

 draughtsmen and engineers for geometrical and mechanical 

 drawing. [2, 6, 13, 15, 17, 20, 21, 24, 25, 27.] 



Maxim Fire-Director and Protractor. A protractor designed 

 especially for use with the Vickers gun and Mark VII. S.A. 

 ammunition. [20.] 



Maximum Registering Aneroid. For registering the maximum 

 altitude attained. See Barometer. [2, 6, 13, 15, 17, 20, 21, 

 24, 26, 27.] 



Maximum Thermometer. See Thermometer. [2, 5, 6, 13, 15, 

 16, 17, 20, 21, 24, 25, 26, 27.] 



Maxwell's Vibrating Needle. An apparatus for finding the 

 modulus of torsion of a wire by observing the times of 

 swing of tubes of different moments of inertia which are 

 suspended from the wire under test. [4, 19.] 



Mclnnes Indicator. Improved form of engine indicator (q.v.). 

 [13, 15, 16, 17, 28.] 



Meanometer. A boxwood scale divided with the various indicator 

 scales, and having a sliding index for ascertaining the mean 

 pressure of steam from an indicator diagram. [13, 15, 28.] 



Measuring Microscope. A special form of microscope for work- 

 shop use for the accurate measurement of small distances, 

 e.g., by the use of an eyepiece micrometer or of a micrometer 

 screw by means of which the microscope can be traversed. 

 [2, 3, 4, 6, 10, 14, 19, 21, 22, 25, 26.] 



