420 



MODELS FROM SERIAL SECTIONS 



[Ch. XI 



§ 681. Condensers to use with the small outfit. — For low powers, 

 50 to 16 mm., the substage condenser of the microscope can be turned 

 aside and the small condenser with the lamp alone employed. In 

 many cases no ocular is used for the sake of the large field. For powers 

 of 8 to 2 mm. when the ocular is used it is necessary to use the sub- 

 stage condenser to light with the proper aperture. And if the oil 

 immersion is used it is a great advantage to make the substage con- 



FiG. 247. Drawing anb Peojecpion Outfit. 



For fidl explanation see Fig. 109. For drawing the 6-volt lamp can well take 

 the place of the arc lamp here shown (§676). 



denser homogeneous immersion also; that is, to have some of the 

 homogeneous immersion fluid between the lower side of the sHde 

 and the condenser as well as between the objective and the cover- 

 glass (§471)- 



§ 682. Making the drawings. — One can draw directly upon blot- 

 ting paper, but it is so important to have a drawing to refer back to 

 that one or more duplicates should be made. This is easily accom- 

 plished by putting a sheet of carbon manifolding paper on the blot- 

 ting paper and a sheet of thin paper over the carbon paper, using 

 thumb-tacks to hold the blotting paper and the dupUcating sheets 

 in position. 



