392 Mr. T. Proctor Hall on New Methods of 



laboratory. Under the shelf was a wooden closet having a 

 door in front, a zinc top, z, and a pipe, /, leading to a venti- 

 lating-flue. The liquid to be examined was placed in a deep 



Fig. 2. 



Fig. 3. 



glass evaporating-dish, which sometimes was fitted with a 



ground-glass cover, and rested upon the specially 



constructed arm of a heavy retort- stand, so 



arranged that it could be raised or lowered 



several centimetres by turning the screw-handle, 



s, outside the closet. Arrangements were also 



made for stirring the liquid by twirling in the 



fingers the end of a long-handled glass stirrer 



(fig. 3), and also for changing the glass frames, 



without opening the closet-door. 



The liquid was placed so that its surface was 

 10 or 15 millim. below the bar m (fig. 1) of the 

 frame. The latter was lowered into the liquid by 

 tipping the balance-beam. 



For work in which an error due to a change 

 of half a degree in temperature may be neglected, such an 

 arrangement is very satisfactory. But if it is desired to find 

 the surface-tension at high or low temperatures, and especially 





