A Versatile Pipet Bulb A recent note in THIS JOURNAL' describes an inexpensive pipet bulb constructed from commercial parts. We have constructed an even simpler and less expensive pipet bulb from readily available rubber hulhs and polyethylene or other plastic tubing. The device is formed from plastic tubing by using ordinary glass working techniques. Reference to the sketch below will enable one to understand the two simple operations. The two operations involve 1)drawing out a tapered section as one would draw out glass tubing for capillaries, and 2) farming a collar to prevent the device from slipping too far into the rubber bulb. The collar is formed by warming the plastic tubing just above the tapered part and gently pushing the tubing ends toward each other. Of course the order of the two constructions may be reversed. The device is cut to appropriate length and then is inserted in a rubber bulb for use on the inside of pipets. Construction time is shout two t o three minutes per item.
' Deckey, G., J. CHEM.EDUC.,57,526 (1980). H. D. De Witt Westminster College New Wilminglon, PA 16142
Volume 58
Number 9
September I981
733
