'69 



near (op of cabinet) so as to reduce the soiincl of liuininer in t('lej)hono 

 receivers as ninch as possible, ])eing sure tliat the connection from 

 the third branch to the shiehl is functioning ))ro]ierly. The ground 

 switch shouhl be kept open at all times excej)t diu'ing this test. It 

 may be necessary, however, to niake tliis adjustment every day. 



4. Again adjust the setting of slide wire so as to reduce as much as 

 ]M)ssible the sound of the hummer in the telej)hones — this gives the 

 salinity of the water being tested. 



There are two "X" cells, but oidy one can be in circuit at a time. 

 Either one may be used in testing samples. It is customary to fill 

 both cells with water and let them both come up to tcmju'rature at 

 the same time, and both sam]:>les can be tested at practically the same 

 time by shifting the wires from one to the other. The ''X" cell is 

 omi ticfl by connecting a rubber tube to the glass discharge ])i]>e and 

 blowing through the lilling tube. If the end of the rubber hose is 

 below the level of the bottom of the cabinet the water will sj-phon 

 out of tlie coll. "^^Tien rinsing <Hit the cell kec]) the lubber hose on 

 the discharge lube and fill the cell with water to be tested, sy])hon 

 out (his water and remove the rubber hose, then fill the cell with the 

 wa(er to be tested. A glass stopper should be ]>laced in tube after 

 filling the cell and ke]:)t there during the salinity test. There is 

 suflTicient water in a citrate bottle to ]iermit rinsing of the cell. 

 It is always advisable to bring the water in the citrate bottles close to 

 the testing temperature. This will speed up the testing work, as the 

 greatest delay is caused by waiting for the sample under test to come 

 U]i to testing temperature. Fifteen minutes is enoujrh to allow for 

 the cell to acquire the temjieiature of the batli. 



Table of data concerning scientific stations occupied during 1925 



