400 THE NEW WORLD OF SCIENCE 



by any rigid rule. On the contrary, they were encouraged to 

 make every possible innovation in the manner of attack, in 

 order that obscure sources of error might be discovered and 

 the highest possible accuracy in the final results attained. The 

 outcome demonstrates most conclusively that organized effort 

 and freedom of initiative are by no means incompatible. Im- 

 portant instrumental improvements of many kinds were effected, 

 sources of error previously unsuspected were brought to light, 

 and means of eliminating them were devised. A by-product of 

 the investigation, of great fundamental interest, was the dis- 

 covery that the peculiar displacements of certain lines in the 

 spectrum of the electric arc, which are greatest near the nega- 

 tive pole, are due to the influence of the electric field. These 

 displacements, previously unsuspected, are sufficient to render 

 such lines wholly unsuitable for use as standards unless rigor- 

 ous precautions are observed. The international committee, in 

 the light of the new information thus rendered available, will 

 now have no difficulty in completing its task of determining the 

 positions of standard lines with an accuracy formerly unattain- 

 able. 



The variation of latitude is another subject in which inter- 

 national cooperation has yielded important results. It was 

 found some years ago by astronomical observations that the 

 earth's axis does not maintain a fixed direction in space, but 

 moves in such a way as to cause the earth's pole to describe 

 a small but complicated curve around a mean position. The 

 change in the direction of the axis is so small, however, that 

 the most accurate observations, made simultaneously at differ- 

 ent points on the earth, are required to reveal it. These were 

 undertaken at several stations widely distributed in longitude, 

 in Italy, Japan, and the United States. A new photographic 

 method has recently been devised which will probably render 

 unnecessary the use of more than two stations in future work. 



An extensive cooperative investigation planned by the Divi- 

 sion of Geology and Geography of the National Research Coun- 

 cil involves the joint efforts of geologists and chemists in the 



