46 THE NEW WORLD OF SCIENCE 



plication of the principles of physics to warfare was made in 

 the field of airplane photography. In this field as in those of 



., submarine detection and sound-ranging, though not in that 

 of amplification, we followed the developments of the British 

 and the French, though contributing important elements our- 

 selves. The war could scarcely have been fought at all with- 

 out the airplane photographer who was the very eyes of the 

 army. American developments in this field were organized 

 by the Science and Research Division of the Signal Corps which 

 in the summer of 1917 assembled a group of physicists and 

 photographic experts under the direction of Dr. H. E. Ives. 

 This group in closest cooperation with the Eastman Kodak 

 Company of Rochester and the Burke and James Company of 

 Chicago developed what are probably the finest airplane cameras 

 in existence. In addition it developed color filters for detect- 

 ing camouflage and increasing visibility of such value that forty 

 thousand of them were used in the army and navy. It pro- 

 duced new dyes for use in the production of pan-chromatic 

 plates designed to be used for the penetration of haze in air- 

 plane photography and made other advances in this important 

 art which bid fair to revolutionize the whole process of sur- 

 veying, since an airplane photograph taken in a few seconds 

 can give information which it used to* take months to acquire 

 by laborious triangulation methods. 



The fifth* great new. application of physics to warfare lay 

 in the developments in meteorology and in the principles of 

 ballooning. The realization of the possibility of non-inflam- 

 mable helium balloons and the actual production of small 

 propaganda balloons which dropped their loads a thousand 

 miles, from the starting point are among the most spectacular 

 and interesting scientific developments of the war, but neither 

 of them played any actual part in achieving the victory. Of 



^'untold importance, however, was the careful though unspec- 

 tacular work of the meteorological section of the Science and 

 Research Division of the Signal Corps which by thousands 

 of pilot balloon flights accumulated the data that not only aided 



