Journal of Applied Microscopy. 



15 



three-way valve and a short section of 

 rubber tubing. The receiver is made 

 from a section of heavy brass tubing ten 

 centimeters long and three centimeters 

 in external diameter. The open end is 

 closed with a piece of ground glass 4x4 

 centimeters. The base of the receiver is 

 fitted to an L-shaped connecting tube of 

 convenient length. This tube is fur- 

 nished with a three-way valve, which 

 will give a straight connection between 

 the pump and the receiver, between the 

 pump and the open air, between the 

 receiver and the open air, or will close 

 all of these connections. The second 

 arm of the L may be fastened to a 

 wooden base or the wall by means of a 

 staple, or, better, by means of two 

 wooden blocks and a metal strip as 

 shown in the figure. The tubing con- 

 necting with the filter pump should be no 

 longer than absolutely necessary, since 

 thii smaller the amount of enclosed air 

 the more rapidly will exhaustion be 

 accomplished. When the receiver is in 

 an upright position, as shown in the cut, 

 a small bottle containing material may 

 be inserted, or the receiver may be 

 brought down to a horizontal position 

 and a mounted slide inserted. The 

 change of position can be made instanta- 

 neously. 



This apparatus is very effective and 

 rapid in its action, stnce the full exhau-3- 

 tion power of the pump is used inside of 

 two minutes, and the only precaution 

 necessary before removing the material 

 is a half turn of the stopcock. If the 

 pump should be stopped when the way 

 into ihe receiver is open, water will be 

 drawn into the chamber. This Is true 

 of all receivers exhausted by water 

 pimps, however. 



The apparatus described above with a 

 filter pump can be constructed for five 

 dollars or less. 



University of Minnesota. 



New applications of old methods should 

 be sent to the Journal. 



An Improved Form of Wash-Bottle 

 for Microscopists. 



The accompanying cut represents a form 

 of wash-bottle which has been in con- 

 stant use in my laboratory for the past 

 year, and has given great satisfaction. 



n 



fr 



turn 



^\ 



It was devised by Mr. A. L. Winton of 

 the chemical department of this station, 

 and I am indebted to his courtesy for 

 permission to publish the following 

 description of it. The principle employed 

 is that of the siphon, and the apparatus 

 consists essentially of a wide-mouthed 

 bottle fitted with a rubber stopper, 

 through which two glass tubes pass, the 

 one, "A," serving to admit air, the other, 

 "B," to secure a flow of water. One end 

 of the latter extends downward to a 

 point near the bottom of the bottle, the 

 other is cut off about on a level with 

 the stopper and is conected by means 

 of a piece of rubber tubing with a short 

 section of glass tubing, "C," which Is 

 drawn out into a fine open point. The 

 rubber tube is about two inches long 

 and into it is forced a solid glass bead 

 a trifle larger than the inside diameter 

 of the tube "D." A ball-cock is thus 

 formed such as is used in a burette. 

 The bottle having been filled with water 

 and the stopper and glass tubes 

 adjusted, the rubber tube with the bead 

 inserted at its middle point and the 

 nozzle connected with its lower end is 

 connected with the end of the discharge 

 tube, whereupon a slight pressure on 

 the bead and simultaneous suction at the 

 nozzle serves to fill the siphon and the 

 normal atmospheric pressure maintains 

 this condition. To secure a fiow of 

 water all that is necessary is to apply 

 pressure between the thumb and finger 

 upon the rubber tube immediately over 

 the bead "D." The walls of the tube 

 are thus expanded in a direction at right 

 angles to the plane of pressure, the 

 water fiows past the bead and Is dellv- 



