THE ;)ACTf;KIOLOGlCAL MICKOSCOPE. 



77 



thi; flat of tJie fluujfj may bo utilisod. Great care sliould bo taken 

 to have the wick evenly trimmed. The best paraffin oil should 

 be burnt, and it is as well to add a .small lump of camplior. The 

 inotal chimney lias an apei'tiire in front, giving exit to tlie I'ays of 

 light, which is closed in }»y a slip of glass. The glass Ls very liable 

 to crack when exposed to the full force of the flamo, and it is as well, 

 thei-efore, to be provided with a stock of glass slips, which have 



Kic. 22.— Lakck Michosi'OI'K Jj.\.m)'. 



lieeri anneajod liy being enveloped in a, cloth a,nd boiled foi' two or 

 three liours. 



The flat of the flame is used with low powers. The imago of 

 fhe llaino is nsdocted by a plane miri'oi-, and a bidl's-eye condenser 

 iiiter'po.s(td between th<! lamp and the min'or to give an equal 

 illuminati<in of the wliolo field. Jn wo)'king with high powers the 

 hi,mp is turniid with the flamo (•dgewis(;, and the mirror is dispen.sed 

 with. By working, as it is ter'mod, directly on the edge of the 

 flame, the illumination is greatly increased, and a band of light can 



