1918 



Journal of Applied Microscopy 



Some Improvements upon Apparatus for Water Analysis. 



Simple devices often lessen work and frequently with an increase in accuracy. 

 Such devices are more than welcome in the water laboratory, where a large num- 

 ber of samples is handled and where so many of the processes are tedious and 

 time consuming. It is with this thought in mind that the writers venture to 

 present descriptions of two contrivances which have proved their usefulness in 

 this laboratory, where many samples have been analyzed weekly in connection 

 with the problems of the Chicago Drainage Canal. It may be that both of the 

 schemes here presented are old, but if so, we are not aware of it ; in any event 

 they are good, and no harm can result from calling attention to them. 



AN IMPROVED NESSLER CABINET. 



Prof. Palmer of the University of Illinois is the inventor of the original form 

 of cabinet and it has been in use in his laboratory at Champaigne, 111., for several 

 years. The form of cabinet here described differs from the original in that it is 

 constructed so that the sample may be moved along in front of the row of 

 standards. It facilitates work and conduces to accuracy by enabling the analyst 

 to see all of his standard at one time. 



It is operated, as may be seen by referring to the accompanying figure, by 



placing the standards in a 



Vi ^ — — ' 'y '^ -r 



row on a glass shelf and 

 passing light through 

 them to the eye of the 

 analyst by means of two 

 adjustable mirrors. The 

 sample to be estimated 

 may be moved along near 

 the row of standards until 

 it is directly opposite the 

 one corresponding most 

 nearly to it. 



The details are as fol- 

 lows : The standards are 

 placed on the glass plate, 

 " 1," which is supported by the shelf " 2," and the bottoms of the tubes are kept 

 from slipping by the block " 3 ". The top of the tube is steadied by the perforated 

 shelf " 4 ". There should be accommodations for the full number of standards 

 which is used, say eighteen or more. When the tube is in position, the mirror 

 m' is so adjusted that the light from the proper part of the sky is reflected 

 through the standards. The mirror m" is adjusted so as to reflect the beam 

 at a convenient angle for the analyst to read. To avoid superfluous light the 

 standards should all be placed in at once, thus filling all the holes. The sample 

 to be estimated is placed on the glass over the slot S and held by the hand in 

 a position parallel to the standards, then moved sidewise till opposite the stand- 

 ard which is closest to it in value. It is convenient to place a board behind 



•^^ 



front V'Vw. 



'—U-' 



S«t. 



An Improved Nessler Cabinet. 



