3J0 



The Microscope. 



B 



AN APPLIANCE FOE MAKING PHOTO - MICKOGRAPHS 



WITH THE MICROSCOPE IN THE UPRIGHT 



POSITION. 



SENECA EGBEBT, M. D. 



T WISH to call attention to a simple appliance, by means of which 

 -*■ photo -micrographs may be made with the microscope in an 

 upright position, and by the use of almost any amateur camera. 



It consists of two short brass tubes, fitted to one another at 

 right angles, and having fixed at their junction a right-angled, 

 isosceles prism with its hypothenuse silvered, thus forming a perfect 

 mirror. 



E. I The vertical tube A should fit 



smoothly in the draw- tube of the 

 microscope to be used, taking the 

 place of the eye-piece ; while the 

 horizontal tube B should be large 



1 enough to receive the eye-piece in 



case it is desired to use the appli- 

 ance as a camera lucida. If this 

 prism-tube be slipped into the 

 draw-tube of the microscope, it is 

 evident that if the angle of the 

 prism be exactly 90° and the sides 

 true, the rays of light coming through the objective and striking 

 upon the surface CD, will be reflected from the surface CE and pass 

 through the tube B without distortion, whence they can be received 

 upon the ground glass or dry plate of any camera that may be con- 

 nected by a light-tight cone with the projecting end of the tube B. 

 Some of the advantages that may fairly be claimed for this 

 appliance are: 



a. Simplicity. 



b. Absence of any vibration, either in microscope or camera. 

 This is a serious objection to all devices for suspending or support- 

 ing the camera above the microscope. 



c. The ability to photograph objects in fluid media; e. g., the 

 growth of crystals and of low forms of life (as the Amoeba or Oscil- 

 latoria). I am even confident that, with sufficient light from a good 

 heliostat, instantaneous photographs may be obtained of some of 

 our moderately lively infusoria. 



d. Its applicability to instruments which have no hinge and 

 which cannot be tipped to the horizontal position. 



Fig. 1. 



