and Laboratory Methods. 



1889 





LABORATORY PHOTOGRAPHY. 



Devoted to Methods and Apparatus for Converting an Object into an Illustration. 



PHOTOMICROGRAPHIC CAMERA. 



A SIMPLE VERTICAL 



One of the chief factors in securing well defined images with the photo- 

 micrographic camera with moderately high power objectives, is perfect rigidity 

 and stability, while in order to make it practical and workable it should be so 

 arranged as to be adjustable both as to 

 length of bellows and in relation to the 

 microscope, and at the same time capable 

 of being fixed rigidly in the desired posi- 

 tion. To secure these ends, the construc- 

 tion shown in the accompanying engraving 

 has been adopted. The base plate for sup- 

 porting the microscope and the camera 

 consists of a heavy iron casting with hori- 

 zontal pillar into which is fitted a vertical 

 steel rod one meter long. A thumb screw 

 in the back of the supporting pillar bears 

 against the rod and prevents its vibration, 

 or rotation. A groove around one-half the 

 circumference of the rod receives the end 

 of the thumb screw and limits rotation to a 

 half circumference. The camera bellows 

 is attached to the vertical rod by means of 

 two sleeves with thumb screws which bear 

 against the vertical rod, holding the bellows 

 in any desired position. Lateral motion is 

 prevented by a longitudinal groove in the 

 back of the rod which receives the thumb 

 screws. It will thus be seen that a micro- 

 scope placed upon the base plate can be 

 brought to the center of the camera bellows 

 when rotated to the limit of motion over 

 the stage plate, and when the microscope 

 is so centered, a locking gauge, shown at 

 the front of the upper surface of the base 

 plate, is brought up against the front of the 

 microscope and clamped. The connection 

 between the microscope and camera is made 

 by a light-tight chamber, the front of the 

 camera being dropped down by loosening 

 the thumb-screw of the sleeve. The ground 

 glass is then adjusted to the proper distance, 

 when the apparatus is ready for exposure, 

 object under the microscope the lower portion of the bellows is raised by loosen- 

 ing the thumb-screw and sliding the camera upward until the light-tight chamber 

 is disengaged, when the thumb-screw on the supporting pillar is loosened and 

 the camera may be swung to the left a half rotation out of the way of the micro- 

 scope entirely, permitting the use of the instrument just as though it were not 

 in connection with the camera at all. This makes the instrument particularly 

 convenient for recording observations on living forms, and for general work. 



L. B. E. 



A New Photomicrographic Apparatus. 

 When it is desired to adjust the 



