368 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1912. 



relation in which these ingredients stood one to another — that is, 

 which of them were necessary and which merely incidental — and in 

 what compounds and what proportions the necessary ingredients 

 required to be present, has never been satisfactorily established. 

 When we know the stable compounds which lime, alumina, and 

 silica can combine to form, together with the conditions of equi- 

 librium between these for different temperatures and percentages 

 of each component, a formula can be written offhand for a success- 

 ful Portland cement from given ingredients somewhat as an experi- 

 enced cook might write out the recipe for a successful dish. Such 

 definite and vahiable knowledge is not beyond our reach. To 

 obtain it requires in fact precisely the same system of procedure 

 which has been described above and which has already been suc- 

 cessfully applied to many of the natural minerals which have been 

 reproduced and studied in the Geophysical Laboratory during the 

 past five years. It happens that we have examined a considerable 

 number of these very mixtures in our recent work upon the rocks. 

 All the compounds of lime, silica, and alumina have been established, 

 and a portion of the silica-magnesia series and their relations have 

 been definitely determined throughout the entire range of accessible 

 temperatures. There is no reason to apprehend serious difficulty 

 in applying the same procedure to the commercial ingredients of 

 Portland cement and replacing the present rule-of-thumb methods 

 and uncertain products with dependable cements. The problem 

 of determining the relation of the ingredients in commercial cement 

 and the conditions necessary for its successful formation is exactly 

 the same in character as that of determining the conditions of for- 

 mation of the rocks of the earth. 



A physico-chemical investigation of the sulphide ores over a wide 

 range of temperatures and pressures has also been undertaken, 

 which has developed a large body of exact information of value in 

 mining industry. And such illustrations could be continued almost 

 indefinitely if it would serve any useful purpose to do so. 



The industrial world is not, as a rule, interested in scientific prin- 

 ciples; the principle must first be narrowed down to the scope of 

 the industrial requirement before its usefulness is apparent. The 

 immediate effect of an industrial standpoint is therefore to restrict 

 investigation at the risk of losing sight of underlying princi])les 

 entirely. An illustration of this has come down to us through the 

 pages of history, of a character to command and receive the utmost 

 respect, for such another can hardly be expected to occur. We have 

 honored the early philosophers for their splendid search after broad 

 knowledge, but in what is now the field of chemistry they allowed 

 themselves to be turned aside to the pursuit of a single 

 strictly utilitarian problem — the transmutation of base metals into 



