686 THURAS: RECORDING SEA-WATER SALINITY 



CONCLUDING REMARKS 



It is quite probable that this recording salinometer and the 

 recording thermometer mentioned in the first paper can also be 

 used, with some modifications, to measure the physical properties 

 of sea water below the surface, at least to moderate depths. This 

 method of observation at various oceanographic stations would 

 seem to be far more advantageous than the present instruments 

 used for this work. These advantages are, first, many more ob- 

 servations could be made in the same length of time; secondly, 

 the observations would be immediately available for correlation 

 and study; thirdly, a corroboration of any doubtful data could 

 easily and quickly be made. 



Recently some other important recording instruments have 

 been designed and built for oceanographic research. A current 

 meter, designed by Hans Pettersson,^ has been successfully used 

 to obtain the direction and velocity of the currents in the North 

 Sea and along the coasts of Norway and Sweden. This meter 

 can be suspended at various depths below the surface by means 

 of a special anchor and buoy and will automatically register 

 both direction and velocity for a period of two weeks. 



R. A. Daly* and H. C. Clark have also designed and con- 

 structed a deep sea thermograph which will give a high degree 

 of accuracy. This instrument is also automatic and will give a 

 record of the temperature at any depth for a period of one week. 



Systematic observations with a number of these automatic 

 thermographs and current meters supplemented with a continu- 

 ous record of surface salinity and temperature, and also salkii- 

 ties and temperatures below the surface at various stations, 

 greatly increase our knowledge of ocean circulation. Such ob- 

 servations made simultaneously and at definite intervals through- 

 out the cross-section of an ocean current, as for instance the Gulf 

 Stream, would yield results of great scientific value. 



5 Quart. Journ. Met. Soc. London 1915. Monthly Weather Review, May, 

 1917. 



* Dr. Daly recently informed me that a description of this thermograph will 

 soon appear in an issue of the Bulletin of the Museum of Comparative Zoology, 

 Harvard University. 



