GEOPHYSICAL LABORATORY. 9 1 



a few types, but it has not been able to include many applications to other 

 mineral or rock species, even when nearly related to the type studied, or to 

 exhaust the possibilities of any portion of the field. Such studies must await 

 a cooperative effort among the university or other laboratories interested, 

 and some extension of existing facilities. The success of such studies, when- 

 ever and wherever they may be undertaken, is already assured. 



It seems a proper time to call attention to another branch of activity upon 

 which considerable emphasis was laid by the joint committee of distinguished 

 physicists and geologists whose report is contained in the first Year Book of 

 the Institution. I refer to the study of vulcanism by direct application of 

 laboratory (quantitative) relations and methods. This problem was also one 

 of three specially designated by Dr. Becker in his project for geophysical 

 research, which is contained in Year Book No. i. In the development of 

 geophysical research in the laboratory since that time, it has seemed wise to 

 postpone the serious consideration of so broad and important a subject until 

 the methods and equipment should be developed to a point where such con- 

 sideration might be expected to yield something more than mere speculation. 

 During the past year, however, an opportunity was afforded the Laboratory 

 to make a preliminary study of an active volcano. The occasion was an ex- 

 pedition organized by Professor Jaggar, of the Massachusetts Institute of 

 Technology, to visit the active crater of Kilauea, in the Territory of Hawaii, 

 one purpose of which was to stretch a cable across the crater and to make an 

 accurate measurement, for the first time in the history of volcanic study, of 

 the temperature in the middle of the active lava basin. The Laboratory was 

 invited to make plans for appropriate apparatus for measuring this tempera- 

 ture, and to send a representative to carry out the measurements at the crater. 

 The invitation was accepted, and in pursuance thereof specially designed ap- 

 paratus was built, tested, and j\Ir. Shepherd, of this Laboratory, spent two 

 months of the past summer measuring the temperature in the midst of a boil- 

 ing lava basin i,ooo feet or more in diameter. Of the result it may be said 

 that although three sets of apparatus were destroyed by the lava, an accurate 

 measurement of the temperature in the most active portion of ^the crater was 

 obtained. The temperature was 1000° C. 



The participation of the Laboratory in the enterprise projected by the 

 Massachusetts Institute of Technology ends with the successful accomplish- 

 ment of the work for which it assumed the responsibility, and nothing fur- 

 ther need be said of it in this place. But it afforded an opportunity for a 

 member of our own staff, experienced in the laboratory study of the relations 

 of the minerals, to examine into the character of the problems offered by an 

 active volcano and the possibility of oft'ering a positive answer, through labor- 

 atory study, to some of the vital questions about the formation of the earth. 



Without entering too intimately upon details, the result of this preliminary 

 examination makes it appear entirely practicable to learn something of the 

 sources of volcanic energ}' through laboratory study of the reactions going 

 on in an active crater. 



