SCIENTIFIC r.ESlTLTS 



175 



i-et'ont years. The fact that the vohime of radio traffic handled by 

 the patrol in the last five years alone has increased 300 per cent, is 

 eloquent testimony of the use of this ice service by North Atlantic 

 shipping. 



LANE ROUTES AND THE CRITICAL ICEBERG AREA 



FiGDRE 112. — The location of the principal trans-Atlantic 

 lane routes which are explained in the text, page 171. The 

 shaded portion of 20.000 square miles represents the ice- 

 herg area which receives the international ice patrol s 

 most vigilant attention. Bergs in this area are potential 

 menaces, liable at any time to drift southward across the 

 paths of the trans-Atlantic traffic. The ice patrol during 

 the past few years has attempted to keep on board an 

 up-to-date current chart of this area. A satisfactory 

 map according to P.jerknes's method, can be constructed 

 from a Total of IS points of observation, as shown above. 



One of the most iiiterestin<; scieiitiHc aids which the patrol is 

 using with considerable success is that of current mapinng according 

 to the Bierknes theory of dynamic oceanograj^hy. The patrol by 

 keeping an up-to-date cuvwut map of a 20,000 square mile area soutli 

 of th.' (Irand Bank, at the junction of the Labrador current and the 



