GEOPHYSICAI, RE;SEARCH — DAY. 177 



Day, Afthttr L., U. S. Geological Survey, Washington, District of Columbia. 

 Grant No. 334. Investip;ation of mineral sohdion and fiisioji wide? high 

 temperatures and pressures. (For previous reports see Year Book No. 3, 

 p. 80, and Year Book No. 4, pp. 224-230.) $17,500. 



With the work of the present year our studies of mineral fusion and solu- 

 tion in the laboratory may be said to have passed beyond the preliminary 

 stage. It has been found thoroughly practicable to study several of the 

 important problems in mineral formation by applying the principles and 

 methods of physics and physical chemistry at the temperature where the 

 formation actually occurs, and to carry out the quantitative determinations 

 with an accuracy entirely comparable with the more conventional physical 

 and chemical research at ordinary temperatures. It is therefore a great 

 pleasure, at the close of the largest year's work which we have yet under- 

 taken, to be able to express our renewed confidence in these methods and our 

 full expectation that they will soon be generally adopted and applied to 

 build up a quantitative science of mineral solutions which will place our 

 knowledge of the minerals composing the accessible portions of the earth on 

 the same level with the long respected "exact" sciences. In expressing this 

 confidence in the coming development of a quantitative science of petrology, 

 I am not unmindful of the time factor involved. Exact research is slow and 

 the opportunities for it limited ; but, on the other hand, I doubt if any exten- 

 sive field of research was ever entered upon with more certain assurance of 

 a successful future. 



The essential novelty of the present plan, when freed from all technical 

 terms and expressions, is this : It has been the habit heretofore, in investi- 

 gating the makeup of the earth, either to study natural minerals in which, of 

 course, the formation process is already complete and no longer accessible, 

 or to study artificial minerals in the same way after actual formation is over. 

 Our plan has been to transfer the investigation as far as possible to the region 

 where the earth-making processes are at work, and to observe the minerals 

 during actual formation. Only in this way, in my opinion, can we succeed 

 in ascertaining which forces are essential and which are merely incidental to 

 the operations under observation, and in measuring their magnitude. Then 

 only does it become possible to treat mineral solutions at high temperatures 

 substantially like other chemical solutions at lower temperatures, and to 

 utilize the experience gathered by miodern chemistry during the last quarter 

 of a century. 



The method of actual procedure and the progress so far made can also be 

 outlined in a general way quite briefly. We must begin with the simplest 

 problems, and proceed in an orderly way to those more complicated — first, 

 the properties of single minerals over the entire range of their stable existence 

 (solid and liquid) ; then combinations of two, in which both remain stable; 



