121 



Meridian Circle. A transit instrument with a graduated circle 

 securely fastened at right angles to the horizontal axis, 

 and turning with it. [10, 21, 24, 25, 27.] 



Meridian Instrument. Any astronomical instrument having a 

 telescope that revolves in a meridian plane. [10, 18, 21, 24, 

 25, 27.] 



Meridian of a Globe, or Brass Meridian. A graduated circular 

 ring of brass, in which the artificial globe is suspended and 

 revolves. [13, 15.] 



Metal Bending Tester, Sankey's. A workshop instrument for 

 testing steel and other metals by observing the energy 

 required to break a small test piece by repeated bending. 



Meteorograph, Dines's. An instrument used in investigations 

 of the upper atmosphere. Made in two forms : (A) Con- 

 sisting of a barograph (q.v.) and thermograph (q.v.) marking 

 on very small, silvered copper plates which are subsequently 

 examined under the microscope ; this form is attached to a 

 small balloon. And (B) Consisting of a barograph, thermo- 

 graph, hygrograph, and wind-velocity recorder, the four 

 records being made on a circular paper chart ; this form is 

 attached to a kite. [6, 13, 17, 21.] 



Meteor ometer. An apparatus for receiving at a local station, 

 transmitting to a central station by telegraph, and there 

 recording the direction and velocity of the wind, condition 

 of the barometer and thermometer, and amount of rainfall. 

 [17.] 



Meteoroscope. An instrument used for taking angles and making 

 measurements of the heavenly bodies. 



Meteor Wind Corrector. A celluloid instrument designed by 

 Major Hatfield for i8-pdr. gun. [15.] 



Meter. An instrument for measuring, and frequently for 

 recording automatically, the quantity measured, e.g., gas 

 meter, water meter, electricity meter, etc. [16, 17, 20.] 



Meter, Fluid. An instrument for measuring the quantity of fluid 

 passing a selected point. [4.] 



Meter, Gas Pressure. An instrument for measuring the gas- 

 pressure in gasworks, etc. [17.] 



Meter, Gas Purity. An instrument for the determination of the 

 purity of gas. [4.] 



Meter, Hydro-volume. An instrument for measuring the con- 

 sumption of furnace gas and air. 



Metric Scales. Measuring scales divided according to the metric 

 system for the use of draughtsmen. [2, 5, 6, 13, 15, 17, 21, 

 24, 25, 26, 27.] 



Metrochrome. An instrument for measuring colours. 



Metrograph. An instrument attached to a locomotive for 

 recording its speed and the number and duration of its 

 stops. 



Metroscope. An instrument for measuring inaccessible heights 

 and distances and for levelling. 



