GEOPHYSICAL RESEARCH — DAY. 367 



are not really engaged in the artificial production of gems, and 

 although the seductive character of such an investigation would no 

 doubt appeal to many, it must be admitted that the geological 

 laboratory is not and probably will never become the serious com- 

 petitor of nature in those directions in which nature has produced 

 her most brilliant effects. 



In what has preceded I have laid emphasis upon the value of 

 experimental measurements in the systematic development of a more 

 exact science of the earth. It is a fair Ciuestion, and one which is 

 very often raised, whether all this investigation has a utilitarian side, 

 whether the knowledge obtained in this way and with such difficulty, 

 will help to solve any of the problems arising in the exploitation of 

 our mineral resources or assist in our industrial development. It is 

 neither wise nor expedient, in entering upon a new field of research, 

 to expatiate long upon its practical utility. Its prmciples must first 

 be established, after which there is no lack of ingenuity in finding 

 profitable application of them. 



The development of thermoelectric apparatus for the accurate 

 measurement of high temperatures was begun and has been per- 

 fected in the interest of geophysical research, and it has already found 

 such extended application among the technical industries as to 

 demand the manufacture and calibration of thousands of such high- 

 temperature thermometers every year. The tempering and im- 

 pregnation of steel are no longer dependent upon the more or less 

 trained eye of the workman, but are done at measured temperatures 

 and under known conditions which guarantee the uniformity of the 

 product and admit of adaptation to particular purposes, like high- 

 speed tools or armor plate. This has the incidental but far-reaching 

 industrial consequence that workmen of great individual skill in these 

 industries are much less necessary now^ than formerly. Everything 

 is accomplished by bringing temperature conditions under mechanical 

 control and making them absolutely reproducible without the exercise 

 of critical judgment on the part of anyone. 



A more intimate knowledge of the behavior of the minerals them- 

 selves finds almost immediate industrial application. An industiy 

 which has grown to enormous proportions in recent years is the 

 manufacture of Portland cement, about which little more has been 

 known than that if certain natural minerals were taken in the proper 

 proportions and heated in a peculiar furnace developed by experience, 

 the resulting product could be mixed with water to form an artificial 

 stone which has found extensive application in the building trades. 

 Chemical analysis readily established the fact that the chief ingre- 

 dients in a successful Portland cement were lime, alumina, and silica, 

 with a small admixture, perhaps, of iron and magnesia: but the 



