226 



PHOTOGRAPHING WITH THE MICROSCOPE [Ch. VII 



directly (rig. 131). When the light is satisfactory, as seen through 

 an ordinary ocular, remove the ocular. 



(a) Photographing without an ocular. — After the removal of the 

 ocular put in the end of the tube a lining of black velvet to avoid 



reflections. Connect the microscope with 

 the camera, making a light tight joint, 

 and focus the image on the focusing 

 screen. One may make a light-tight con- 

 nection by the use of black velveteen or 

 more conveniently by the double metal 

 hood which slips over the end of the tube 

 of the microscope, and into which fits a 

 metal cylinder on the lower end of the 

 camera (fig. 133-134). In figure 134 the 

 connection has been made. 



It will be necessary to focus down 

 considerably to make the image clear. 

 Lengthen or shorten the bellows to make 

 the image of the desired size, then focus 

 with the utmost care. In case the field 

 is too much restricted on account of the 

 tube of the microscope, remove the draw- 

 tube. When all is in readiness it is well 

 to wait for three to five minutes and 

 then to see if the image is still sharply 

 focused. If it has become out of focus 

 simply by standing, a sharp picture could 

 not be obtained. If it does not remain 

 in focus, something is faulty. When 

 the image remains sharp after focusing 

 make the exposure. From 20 to 60 sec- 

 onds will usually be sufficient time with medium plates and light as 

 described. If a color screen is used it will require 50-300 seconds, 

 i. e., 2 to 5 times as long, for a proper exposure (§ 372). 



(b) Photographing with a projection ocular. — If the object is 

 small enough to be included in the field of a projection ocular (fig. 



Fig. 133. Light Excluder 

 for Connecting the Cam- 

 era and Microscope. 



(About j natural size). 



1 The front board of the 

 camera. 



2 Connecting piece to fit 

 over z and extend down into 3. 



3 Piece to fit over the up- 

 per end of the tube of the 

 microscope and to receive the 

 lower end of 2 (compare fig. 

 134 where the parts are to- 

 gether as in making an expo- 

 sure). 



