^12 THE AMERICAN MONTHLY [Dec 



currences, frequent observations have been made, but no 

 more of these peculiar growths have formed, although 

 the material still contains living desmids and diatoms. 

 Numerous colonies of minute diatoms enclosed in gela- 

 tine have formed but have not persisted long enough for 

 conclusive results. A drop of the sediment now under 

 observation shows six species of desmids, countless num- 

 bers of empty frustules of large Surirella and a few liv- 

 ing ones, but their number has been constantly diminish- 

 ing for a year past. A few specimens of Surirella bis- 

 eriata still live but are very sluggish. S. splendida are 

 nearly all dead, but active frustules of a very elongated 

 type of S. elegans still survive. I wish those rscientists 

 who believe that the motions of the Surirelhaare confined 

 to a "languid roll" could see one of these ploughing its 

 way through the debris and crossing the entire field of 

 the microscope in a little over one minute. Two or three 

 species of Pinnularia also appear healthy. 



A New Photo-Micrographic Apparatus. 

 A. W. Bitting, Lafayette, Ind. 



The apparatus consists of an upright cast-iron post 

 supported by three cast legs. The center of this post is 

 bored out to receive the elevating post. Near the top is 

 a sprocket wheel, which is turned by a screw and crank. 

 A binding screw is also placed in the top to clamp the 

 elevating post in position. The upright post, with its 

 legs, stands 28 inches high. The elevating post is 28 

 inches long, is of two-inch steel tubing, turned to fit the 

 hole in the upright post. A series of holes are drilled 

 into the tubing to receive the sprocket wheel, which 

 raises and lowers it. Upon top of the elevating post is 

 a head-post which receives the bed plate for carry- 

 ing the camera and microscope. The head-post is turned 



