CH. VII] PHOTOGRAPHING WITH THE MICROSCOPE 



221 



satisfactory for photography. They are employed for this purpose 

 with a special projection ocular. Two low powers are used without 

 any ocular. Some of the best work that has ever been done, however, 

 was done with achromatic objectives (work of Woodward and others). 

 One need not desist from undertaking photo-micrography if he has 

 good achromatic objectives. From a somewhat extended series of 

 experiments with the objectives of many makers the good modern 

 achromatic objectives were found to give excellent results when used 

 without an ocular. Most of them also gave good results with pro- 



FIG. 132. HOME-MADE OPTICAL BENCH. 

 (About T V natural size. From Optic Projection). 



This is composed of a baseboard on which are fastened two rods (t t t t t) 

 to serve as a track along which the different apparatus blocks can be moved. 



The shaded part (as) is covered with asbestos paper to avoid any danger 

 from fire. 



// The flanges holding the sockets for inserting the different pieces of 

 apparatus. (Compare fig. 109-112, 131). 



jection oculars. It must be said, however, that the best results were 

 obtained with the apochromatic objectives and projection oculars. 

 The compensation oculars also give good results. It does not seem 

 to require so much skill to get good results with apochromatics as 

 with achromatic objectives. The majority of photo-micrographers 

 do not use the Huygenian oculars in photography, although excellent 

 results have been obtained with them. An amplifier is sometimes 

 used in place of an ocular. Considerable experience is necessary in 

 getting the proper mutual position of objective and amplifier. The 

 introduction of oculars especially designed for projection has led to 

 the discarding of ordinary oculars and of amplifiers. Oculars restrict 

 .he field very greatly; hence the necessity of using the objective alone 

 for large specimens. 



