1896 THE MICROSCOPE. 169 



Practical Hints for the Worker. 



By B. L. RAWLINS, 

 NASHVILLE, TENN. 



An excellent device in the way of an air pump and 

 receiver for ridding the freshly mounted slide of air bub- 

 bles, may be mad© after this fashion. The pump con- 

 sists of an ordinary small bicycle pump which may be 

 made to exhaust the air from a chamber by simply 

 changing the working direction of the valve and turning 

 the piston leather so that the convexity comes to the out- 

 side instead of the inside of the metal disc. A washer 

 of somewhat smaller size than the disc must also be 

 placed in front of it to keep it from collapsing. 



The receiver is made by fitting two soft rubberstoppers 

 into a glass tube of such length that the chamber left is 

 of sufficient length to act as a receptacle for the slide, 

 and of such width that the slide will easily go in. For 

 want of something better a straight lamp chimney 

 known as the students, maybe cut with a file and ground 

 down smooth. 



Through one of the stoppers a small perforation may 

 be made and a piece of brass tubing which has had a 

 thread cut on it to correspond with the pump nozzle, is to 

 be tightly fitted. With a leather washer to go between, 

 the instrument is ready for use. 



While it is an advantage that a stop cock be inter- 

 posed to secure the vacuum for some time it is notindis- 

 pensible. 



Specimens for imbedding may be put into a short test 

 tube and put in this chamber in order to be rapidly per- 

 meated with the thin celloidin solution. 



The University of the State of New York has decided 

 that after January 1, 1897, no degrees B. A. or A. B. shall be 

 conferred catisa honoris. 



