36 



values are crossed. Well-fixed soundings in the latter places are both 

 interesting and valuable. The sounding work can be carried on 

 without any interference with the primary objects of the ice patrol, 

 and will probably be continued, with the result that each year many 

 additional depth values for use on the charts of the Grand Banks 

 region will be obtained. 



2. STATION WORK 



During the 1930 ice-patrol season 67 oceanographic stations were 

 occupied. Figure 24 shows the location of each station. The first 

 one, No. 1096, was taken on March 2 and the last. No. 1158, on 

 May 31. 



The salinity of every water sample from every station was deter- 

 mined by the electrical conductivity method. The titrating outfits, 

 which were carried for use in case of trouble with the electrical salinity 

 cabinet, did not have to be used. Frequent water samples of known 

 salinity were tested by the electrical method for check purposes. It 

 is believed that the accuracy of the salinity values printed in this 

 bulletin is fully equal to that of the values for 1928 and 1929. 



In addition to getting the salinity and temperature at the usual 

 levels, at a number of the 1930 stations many extra levels in the upper 

 100 meters were sampled. The additional values help to show the 

 rates of vernal warming at different levels below the surface. They 

 indicate the depth of wave mixing, and give, in general, specific infor- 

 mation for many different regions about the Grand Banks regarding 

 the conditions prevailing at levels other than those usually studied. 



Complete station data is printed in the usual form, beginning on 

 page 45. Figures 25-27 show some vertical temperature and salinity 

 sections. Figures 28-29 are dynamic current diagrams. The above 

 five figures were drawn up from the tabulated station data and are 

 probably the most interesting and instructive drawings that can be 

 prepared from the same. 



A few short lines of stations were occupied across the temperature 

 wall for the purpose of studying the verticality of the wall and the 

 special dynamic conditions prevailing near it. The vertical sections, 

 Figures 25-27 contain more or less pronounced examples of such lines 

 of stations. They show that the temperature wall is often very steep. 

 The dynamic gradient across the wall was found to be steep also. 



Figures 28 and 29 depict both dynamic and actually observed cur- 

 rents near temperature walls. At first glance it would seem that the 

 dynamic currents are not in agreement with the actually observed 

 currents indicated by drift of bergs and patrol ship. The trouble 

 lies mainly in the small number of stations occupied. The currents 

 near the wall are doubtless confused and erratic and a network of sta- 

 tions would probably have depicted dynamic currents agreeing much 



