516 Dr. J. W. Evans — Presidential Address. 



accomplished, in spite of somewhat inadequate financial support 

 from the powers that be, who have taken every precaution that the 

 Honours graduates who join its ranks should do so for the pure love 

 of science and not for the sake of worldly advantage. With 

 increased staff and less straitened finances the Survey would be in 

 a position, not only to discharge the additional duties my suggestions 

 would impose on them, but to extend still further the sphere of their 

 usefulness. There is, for instance, at the present time a very urgent 

 need for the provision of further facilities for the analysis of rocks 

 and minerals to assist and complete the researches both of the 

 official surveyors and of private persons engaged in research. The 

 work is of a very special character, and the number of those who 

 have given sufficient attention to it and understand its difficulties 

 and pitfalls is very limited. The chemical staff at our Universities 

 are chiefly concerned with organic chemistry, and private analysts 

 devote themselves mainly to the examination of economic products. 

 The effect of a hasty excursion of workers of either of these cate- 

 gories into the analysis of such complex silicates as augite or biotite 

 or any of our ordinary igneous rocks is apt to be disastrous, only 

 exceeded in this respect by the results obtained when, as not 

 infrequently happens, a student is given a similar task by way of 

 practice. A. certain amount of good work is undoubtedly done in 

 College laboratories, but it is very little in comparison with what 

 is needed. 1 



At present the analytical work of the Survey is organized on 

 a very modest scale in comparison with the personnel and equipment 

 of the laboratory of the United States Geological Survey, though 

 the quality of the work has been as a rule in recent years quite as 

 high. There are two analytical chemists attached to the Geological 

 Survey, and some of the other members of the staff are capable of 

 doing good analytical work. The demand, however, for analyses 

 for economic purposes is so great that it is impossible to carry out all 

 the analyses that would be desirable in connexion with the purely 

 scientific work of the Survey itself. There is consequently no 

 possibility of their being able to assist private investigators. 



Strictly speaking, the individual minerals of a rock should be 

 separately analysed and their relative amounts determined, but this 

 is at present a counsel of perfection that we cannot hope to attain ; 

 and when the difficulty of obtaining pure material, especially in the 

 case of fine-grained rocks, and the zoned character of practically all 

 complex rock-forming minerals are considered, it is seen that 

 intrinsically it is not quite so important as it would seem to be at 

 first sight. The bulk analysis, intelligently interpreted in connexion 

 with the actual mineral composition of the rock as revealed by the 

 microscope, is, in fact, at present the most practical method of 

 determining the composition of the minerals. I need scarcely say 

 that volatile constituents still retained by the rock should be separately 



1 I should like to refer in this connexion to the excellent analytical work of 

 Dr. H. F. Harwood, of the Chemical Department of the Imperial College of 

 Science and Technology. 



