Koenlg.] 



222 



[Aug. 21, 



itself thus far, is the delicacy of the hinge. Yet I have had one in use con- 

 stantly for six months past, and it works as satisfactorily as on the first 

 day. In the hands of beginners it may come out of order sooner. The 

 clamp c is made of brass tubing, with the flanges// and the block g sol- 



^ \ 



_| '^ 



dered on. It is made sufficiently large to admit of variation in the diam- 

 eter of the burette tubes, a strip of paper being used as a filling. The 

 delicacy of the hinge, and to some extent the cost of the apparatus 

 (|2.50) have prompted me to substitute a simpler construction. 



Figures 2a and 25 represent this device. 



The platinum plate is replaced by a piece of pure rubber sheeting, the 

 thickness of strong paper g^ by 3-16 of an inch, which is attached to the 

 end of the spring by means of a solution of rubber. The lower part of 

 the spring may be rendered proof against chemical action by galvanic 

 platinum plating, or by a coating of rubber. The former is certainly the 

 best, but I found by several months' experience, that a spring coated 



