103 



Banks region have already been made, however, and it would seem 

 to be established that they can be made, and that they can be made 

 again whenever necessity arises. A close study of maps already on 

 hand would now seem to be in order, rather than a multiplication of 

 maps of very transient value to the patrol. 



During very light ice years, and at times when all the bergs are 200 

 miles or so to the north of the steamship tracks being used between 

 Europe and the United States, an ice patrol with one vessel only out 

 on duty might be justified in devoting itself to the tasks of dynamic 

 oceanography to the extent of attempting to make detailed current 

 maps of 10,000 square sea mile areas. Even during such times, how- 

 ever, such a procedure is open to question. When the Europe-United 

 :States tracks are not endangered by ice it would seem to be but 

 logical to devote attention to actual patrolling along the southern- 

 most routes between Canada and Europe. The ice patrol, besides 

 being international in name, is entirely so in fact, receiving its support 

 from international contributions, and therefore bound to protect 

 impartially to the limit of its ability all the ice-endangered tracks 

 across the North Atlantic. 



Putting aside this possible exception during light ice years and 

 periods, it would certainly seem that the ice-patrol service as now 

 conducted, that is with two ships alternately out on duty, should 

 most emphatically not devote its activities to oceanography to the 

 extent required for the construction of good dynamic current maps. 

 Depending upon poor current maps is worse than not having any at 

 all. The real solution of the dynamic mapping problem lies in the 

 employment for the ice-patrol duty of an additional vessel, charged 

 primarily with the scientific work. 



3. ESTIMATE OF TOTAL ANNUAL AMOUNT OF GLACIAL ICE SOUTH 

 OF FORTY-EIGHTH PARALLEL, AND ITS TOTAL CHILLING EFFECT 

 ON THE WATER 



It has been argued by a certain school of scientific thought, 

 influenced by the oceanographer, O. Petterson, that the bergs about 

 the Grand Banks in melting furnish the energy which keeps the 

 southern reaches of the Labrador Current moving along as they do. 

 On the other hand, others, and especially F. Nansen, contend that 

 melting icebergs have little effect in producing great ocean currents. 



Attempts to estimate the total amount of glacial ice that comes 

 south of the forty-eighth parallel in any one year and to consider its 

 possible chilling effect on the water masses there may throw some light 

 on this problem. If it is a fact that a negligible amount of cold water is 

 produced by the melting of the bergs that get south of the forty- 

 eighth parallel in the Labrador Current, it will be reasonable to sup- 

 pose that their melting will be unable to have much effect on the hori- 



