eral cc. might be introduced by the intermittent 

 fluctuation back and forth of the mercury col- 

 umn; but ordinarily the error would be rela- 

 tively inconsequential and could be corrected 

 with reasonable accuracy if desired. The most 

 obvious advantages of this style of mounting 

 are (1) that it is possible to detect the presence 

 of air bubbles in the atmometer by simply 

 turning the whole apparatus upside down, and 

 to get rid of them without even taking the cork 

 out of the reservoir bottle; (2) that bubbles 

 can not accumulate in the feed-tube; (3) that 

 any objections which may arise from the use 

 of glass wool are eliminated; and (4) that the 

 mounting is always ready for immediate use. 

 The contrivance can readily be made by any 

 one adept at glass-working or it can be secured 

 from at least one dealer in apparatus and sup- 

 plies for about fifty cents. 



In conclusion, brief attention is called to a 

 modification of the Musch mounting which has 

 been devised by Dr. F. C. Gates (see Fig. 1, B). 

 This modified model recommends itself in being 

 somewhat easier to construct and somewhat 

 more compact and also in the fact that the mer- 

 cury runs more readily back and forth between 

 arm and valve curve than in the original model. 

 This latter feature, however, while of advan- 

 tage in some respects, may prove a disadvan- 

 tage when it comes to the rapid filling of atmo- 

 meter and mount, except where this is done 

 under water (the practise followed by Dr. 

 Gates) or by the suction method: the replace- 

 ment of long air columns and large bubbles of 

 air is interfered with by the very ease with 

 which the mercury slides back and forth. 



G. E. Nichols 



Yale University 



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