398 BELL SYSTEM TECHNICAL JOURNAL 



determine the temperature at which rubber and similar materials fracture 

 under variable bending stress. Although the brittle temperature is sharply 

 defined under high-speed bending through a sharp angle, it is lower as the 

 speed of application or the magnitude of the stress is reduced. In some 

 instances decreases of more than 28°C. in brittle temperature resulted from 

 reductions in bending stress such as might be encountered in service. 



Vulcanized pure gum natural rubber and plasticized polyvinyl chloride- 

 acetate copolymer showed the largest changes, whereas the compounded and 

 vulcanized natural and synthetic rubbers involved in this study exhibited a 

 reduction in brittle temperature from 5° to 10° C. in going from the highest 

 to the lowest stress employed. 



American Science Mobilizes for Victory} Robert W. King. There are 

 no accomplishments of the Bell System in which its men and women take 

 greater pride than those marking the continuous activities in developing and 

 applying the art of communication. 



The Bell Telephone Laboratories' accomplishments, reflected for decades 

 in improved instrumentalities and systems for the transmission of electrical 

 signals and speech, have been possible because vast resources of scientific 

 knowledge have been devoted as part of the System's general responsibility 

 to the public, to a broad and fundamental program of exploration, experi- 

 ment and design. 



Today the more than 6,000 members of these Laboratories are engaged on 

 hundreds of development projects requiring research, invention and design, 

 for the Army, the Navy, and the National Defense Research Committee. 



That this should be both logical and inevitable will not surprise any one 

 who considers the vital part played by communications in modern warfare. 

 Rapid movement of troops and supplies over far-flung lines of action on land 

 and sea and in the air are possible only when directed through effective com- 

 munication systems. More and more the electrical transmission of intelli- 

 gence is becoming the unifying influence pervading all branches of war 

 organizations. It coordinates the movement of naval and aerial fleets; it en- 

 ables infantry, tank columns and formations of aircraft to operate as a single 

 unit. It shrinks a thousand-mile battle line to the compass of a single 

 sector. 



The article by Dr. King points out the place of independent military re- 

 search, although its actual volume is less than that carried on directly by the 

 Army and Navy. It also draws upon experience in industrial research to 

 show that the sudden solution of war problems by appeal to science is scarcely 

 to be expected. 



" Bell Tel. Mag., June 1943. 



