these steamer reports were of immense value in tracking the ice to 

 the northward as the patrol vessel seldom left the areas that were 

 menaced by the ice, and especially those areas near the steamship 

 lanes. These "thousand eyes" of the merchant fleet proved the 

 most valuable aid to the successful prosecution of the ice patrol. 



Dissemination of the information was accompHshed by means of 

 radio, as follows: 



(a) Radio broadcasts. — Regular broadcasts were transmitted twice 

 a day on two wave lengths. (See Radio communication.) 



(6) Special ice Iroadcasts. — In foggy weather or whenever new ice 

 was found a special broadcast was transmitted on 706 meters. 



(c) Special ice data. — ^All positions of ships approaching the patrol 

 or ice-infested areas were plotted whenever communication was 

 established or their positions taken from the water temperature 

 reports. Whenever a vessel was found approaching a dangerous area 

 a special notice covering the latest ice information was transmitted 

 to her, 



(d) Answering special requests from ships. — All ships requesting 

 special ice data were furnished complete information in regard to the 

 ice. 



The oceanographic work was planned so as to occupy stations at 

 certain predetermined points at regular intervals of time and by 

 taking stations alongside of bergs. The location of the ice and the 

 weather at times, however, prevented regularity of schedules, but 

 stations were usually taken at the various critical points. This work 

 consisted of lowering specially constructed bottles, known as Greene 

 Bigelow bottles, secured to a cable at the following depths: 0, 50, 

 125, 250, 450, and 750 meters. After being lowered each, bottle was 

 tripped and closed at its depth by a messenger, or weight which 

 slides down the wire for this purpose, thereupon securing a sample 

 of the water at the various depths and simultaneously inverting a 

 special type of reversible thermometer which registered the tempera- 

 tures at those depths. The samples of water were tested for salinity 

 and the information was compiled and profiles drawn. The data 

 that was obtained determined the character of the water and was of 

 special value in ascertaining the drift of the bergs and the location of 

 the various currents. The salinity of the water was determined by 

 means of the electric salinity tester installed on board the Modoc. 

 A description of the apparatus is contained in the ice patrol report 

 of 1924. Attention is invited to a general resum6 of the practical 

 operation of this apparatus and will be found on pages 67-69. 



Another phase of the oceanographic work consisted in plotting the 

 water temperatures as received from passing vessels and also taken 

 from the patrol sliip's observations. All passing vessels were re- 

 quested, while within a certain prescribed area, to submit to the patrol 



