482 Scientific Intelligence. 



until the United States shall be entirely independent of foreign 

 sources of supply for optical glass." 



Aside from this subject, however, and in the line of the direct 

 work of the Laboratory, Dr. Day has some statements to make 

 which seem so important that they are quoted here at length. 



"A careful appraisement of the situation to-day, after ten 

 years of activity, reveals the fact that the tangible grounds for 

 anxiety about the accessibility of the problems which we then 

 confronted are now for the most part dissipated. It has been 

 adequately demonstrated that the temperature conditions which 

 prevailed during the formative period upon the surface of the 

 earth are well within the reach of known methods of accurate 

 measurement ; that the effects of pressure as a factor hi the for- 

 mation process are insignificant compared with those of tempera- 

 ture, except where volatile ingredients are concerned ; that the 

 established generalizations regarding solutions and the laws of 

 physical chemistry apply broadly to silicate solutions as well 

 as elsewhere ; that the multiplicity of participating substances 

 is not a prohibitive difficulty when these are appropriately 

 grouped for study ; and now, finally, that the fact that some of 

 the substances which participated in the formation process were 

 volatile and disappeared in part from the system in the process 

 of its development is no longer an absolute bar to the competent 

 study of such systems. All this was necessary, and with appro- 

 priate detailed development may be expected to prove sufficient 

 for the competent study of rock formation with its allied prob- 

 lems and applications which was the purpose of the founders of 

 the Geophysical Laboratory. 



' ' The second direction in which the interests of this laboratory 

 have advanced materially during the year is in the progress 

 of volcano study. Perhaps for the first time in the history of 

 volcano observation, laboratory-trained men have stood upon the 

 brink of an active volcanic basin, fully equipped to measure the 

 temperature distribution prevailing deep down in the boiling 

 lava at their feet and to collect appropriate samples both of the 

 liquid and gaseous ingredients which through their inter-reac- 

 tion so largely determine the character of volcanic phenomena. 

 The materials so collected still remain to be studied and no 

 inference at this time can properly forecast the conclusions 

 which will be reached as a result of these studies, but the oppor- 

 tunity presented this year was a rare one and the fact that 

 trained men and appropriate facilities were on the ground to 

 take advantage of it forms one of the bright pages in the history 

 of this elusive science. It will be recalled that volcanoes offer 

 the only opportunity now remaining to science to study the 

 phenomena accompanying the formation of igneous rocks in 

 nature, and by far the greater portion of these must remain 

 entirely inaccessible to man because of the violence of their 

 activity." 



