162 CARNEGIE INSTITUTION OF WASHINGTON. 



even the opal, really made up of a myriad of minute crystalline parti- 

 cles, or is it truly amorphous? 



The fact that every chemical individual is characterized by its own 

 particular effect upon X-rays likewise furnishes us with a method 

 which should serve as a considerable aid to the microscopic methods for 

 the identification of particular rock-making materials. 



Three definite methods have been developed for these investigations 

 of crystalline materials. One of them is based on the original experi- 

 ments of Laue with transmitted radiation and has thus far been the 

 one most used in this Laboratory; another, wherein the X-rays are 

 "reflected" from particular faces of the crystal, has been developed 

 by W. H. and W. L. Bragg; the third comprises the various ways of 

 studying powders and similar material. These three methods have 

 never been used together, nor carefully contrasted with one another 

 to determine their particular fields of usefulness. This Laboratory 

 has been engaged in installing the apparatus necessary for such a 

 critical study and joint use as will result in a more systematic manner of 

 treatment of the problem of studying the structure of crystals. It 

 promises to afford a new mode of attack on the great problem of rock 

 formation, different from any other and of great possible usefulness. 



During the summer a congress of scientists was held in Honolulu, 

 Hawaiian Islands, to discuss for the first time the specific scientific 

 problems offered by the Pacific Ocean and adjacent land areas. The 

 Congress was called together by the director of the Bishop Museum of 

 Honolulu, and an invitation was extended to this Laboratory to be 

 represented by a delegate who might participate in the discussions on 

 volcanology. A few paragraphs from the report of Dr. H. S. Wash- 

 ington, who represented this Laboratory and the American Geophysi- 

 cal Union, will give a brief outline of the purpose and results of the 

 Congress. 



"October 13, 1920. 



" I have the honor to make the following brief report on the activities of the 

 'Pan-Pacific Scientific Congress,' held at Honolulu, August 2 to 20, 1920, 

 which I attended as a delegate from this Laboratory and from the American 

 Geophysical Union. 



"The number of delegates present was 111, representing Australia, New 

 Zealand, Tahiti, the Philippines, Canada, England, Japan, China, and the 

 United States, these last being almost equally divided between the Hawaiian 

 Islands and the mainland. The sciences represented by the delegates were 

 anthi'opology, astronomy, biology, botany, chemistry, entomology, ethnology, 

 geodetics, geography, geology, meteorology, oceanography, seismology, vol- 

 canology, and zoology. 



"After the opening and organization, Herbert E. Gregory being chairman, 

 the activities of the Congress were divided into the following sections : anthro- 

 pology, biology, botany, entomology, geography, geology, seismology, and 

 volcanology. General joint meetings were held daily, as well as meetings of 

 the separate sections, except for the second week, which was devoted to a visit 

 of the Congress to Hawaii and Kilauea. 



