352 



DEPARTMEyT OF THE yiVAL SERVICE 



Ten Eichter reversing thermometers (fig. 3) from Schmidt and Vossberg, cali- 

 brated to 0-1° Centigrade, were in use, two for each water-bottle. For the surface 

 temperatures four thermometers (Schmidt and Vossberg), also calibrated to 0-1"' 

 Centigrade were used. The thermometers were delivered by the international hydro- 

 graphical laboratory at Copenhagen, and were specially tested in the laboratory. With 



Fig. .3. -Richter's re- 

 versing thermometer. 



these thermometers it is possible to read off the temperature to 0-01° Centigrade, but 

 during the expedition the temperatures, after due correction, were rounded off to the 

 nearest 0-05 Centigrade, which was found to be sufficiently accurate for those waters. 



For sending down and hauling up the apparatus two hand-winches with wire 

 reels taking about 5U0 metres of wire were in use, the wire having a diameter of about 

 4 millimetres. A meter wheel of the usual pattern for oceanographical research was 

 used for determining the depth. By the special lateral arrangement for fastening the 

 water-bottles to the wire, several water-bottles could be used at the same time. 



In the laboratory the salinity of the water samples was determined by means of 

 chlorine titration, which is the method mostly used in practical work. The amount of 

 chlorine in sea-water is stated per mille in the same way as the salinity, and defined as 

 follows : — 



By the amount of chlorine we mean the number of grammes of chlorine contained 

 in 1 kg. of water, supposing the small quantities of bromine and iodine to be 

 replaced by chlorine. The amount of chlorine is determined in different ways. The 



