SALINITY APPARATUS 



All excellent description of the electrical salinity apparatus is con- 

 tained in the report of 1924. A general resume of the practical 

 operation is submitted herewith. 



The cabinet containing the apparatus is divided into two com- 

 partments by a vertical partition. The apparatus is shielded by a 

 sheet-copper lining on the inside of each compartment. 



The right-hand compartment contains the following: 



Two "X" cells, one ''Y" cell, one thermo-regulator cell, two heat- 

 ing elements, and a sensitive centigrade thermometer — all immersed 

 in a salt-water bath contained in a copper tank at the bottom of the 

 cabinet. The upper part of this cabinet contains a relay for main- 

 taining constant temperature in the bath and a small motor for 

 stirring the water in the bath. 



The left-hand compartment contains the hmnmer mounted in a 

 hardwood box in the bottom of the compartment, the variable slide 

 wire resistance used in balancing the bridge when making salinity 

 measurements, a head telephone, a variable resistance "Q" in three 

 dials, a variable resistance wound as a cylindrical coil with sliding 

 contact (this is third branch) , a mutual inductance coil, a fixed resist- 

 ance unit, a small single pole-knife SM'itch, three snap switches, and 

 a small push-button switch on left side to close hummer circuit. 



Each compartment is lighted, heated, and kept dry by means of 

 incandescent lights. Electric leads are carried from the cells and units 

 to bus rods running along the under side of the top of the cabinet. 



TO SET UP APPARATUS 



The cabinet, 33 inches wide and 36 inches high, should be supported 

 on a table about 30 inches high, so that the apparatus will be at a 

 height convenient for working. The table and cabinet should be 

 well secured against motion in a seaway. The ship's 120-volt direct- 

 current circuit is the only electric power necessary. 



XoTK. — When iisin^llic apparatus asliore where direcl curreiif is not avaihil)lc 

 it will be necessar}' to insert four dry cells in series in the liuminer circuit. The 

 relay will not operate on alternating currcMil^ that the bath temperature must 

 be regulated by the superheater. This nuiuires ])ractice on the part of the 

 operator. The stirring motor will <i])(_r;ite on llO-volt 6()-cyclc alternating 

 current. 



72733— 2(5t 6 (07) 



