CH. VIII] 



PHOTO-MICROGRAPHY 



231 



Fig. 189. Zeiss' special photo-micrographic stand. It has a very large tube, 

 a slow acting fine adjustment, mechanical stage and all appliances for the most sat- 

 isfactory work. ( Cut loaned by Einier and Amend). 



It will be necessary to focus down considerably to make the image 

 clear. Lengthen or shorten the bellows to make the image of the de- 

 sired 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 

 got out of focus simply by standing, a sharp picture could not be ob- 



