125 



Milk Analyser. See Leff man- Beam Centrifugal Machine ; also 



Lister and Babcock. 



Mine Dial. See Dial, [o, 16, 18, 21, 24, 27.] 

 Mine Explosion Apparatus. A set of instruments devised for the 



investigation of explosions in coal mines. It includes 



circuit-breakers, contact-makers, measuring machine, one- 

 tenth of a second time-markers, and sampling bottles. [4.] 

 Mine Explosion Measuring Machine. An instrument for 



measuring the records obtained from the manometers used 



in mine explosion apparatus, by means of a microscope and 



micrometer screw. 

 Mine Shaft Plummet. A special plummet used in mining work, 



made in several sizes 4f Ibs., 7 Ibs., etc. [21, 24, 27.] 

 Miner's Circumferentor. A form of mining compass with sights, 



used by surveyors for taking horizontal bearings. [2, 13, 



15, 17, 18, 20, 21, 24, 25, 26, 27.] 

 Miner's Dial. See Dial. [2, 5, 6, 13, 15, 16, 17, 18, 20, 21, 24, 



25, 26, 27.] 



Minim Measures. A small graduated glass measure. [17, 20.] 

 Minimum Thermometer. See Thermometer. [2, 5, 6, 13, 15, 17, 



21, 24, 25, 26, 28.] 

 Minute Glass. A glass for measuring a minute or minutes by 



the running of sand. [2, 13, 15, 16, 17, 20, 21, 28.] 

 Mirror. Any glass or polished surface that forms images by 



the reflection of rays of light. [1, 2, 3, 8, 10, 11, 13, 15, 17, 



18, 20, 26.] 

 Mirror, Azimuth. A mirror fitted on the glass cover of a compass 



bowl for taking bearings. 

 Mirror, Fresnel's. Two mirrors fixed at an inclination of nearly 



1 80 to one another for producing interference images. See 



also Parabolic Mirror, Optical Mirror. [3.] 

 Mirror Galvanometer. See Galvanometer. [4, 16, 19.] 

 Mirror, Mangin. A mirror in which the silvered surface has a 



different curvature from that of the outside surface. The 



curves are so chosen that the aberration of the lens so formed 



neutralises that of the spherical mirror. 

 Mirrorscope. A simple form of projection lantern for opaque 



objects. 

 Mitre Square. A bevel square whose blades are set immovably 



at an angle of 45 with each other. [15, 17, 24, 25, 27.] 

 Moderator. An optical device consisting of opal coloured glass 



or ground glass to moderate and diffuse the light passing 



from a lamp to an object on the stage of the microscope. 



[3, 22, 26.] 

 Moisture-Testing Apparatus. For determining the moisture 



content of whole grain. 



Molten Metal Thermometer. See Thermometer. [5, 6, 16, 17.] 

 Monocentric Eyepiece. See Eyepiece. [2, 3.] 



