254 Ford— Growth of Mineralogy, 1818 to 1918. 



line structure upon X-rays. Through the refraction or 

 reflection of the X-ray by means of the ordered arrange- 

 ment of the particles forming the crystalline network, we 

 are apparently going to be able to discover much con- 

 cerning the internal structure of crystals. And, partly 

 through these discoveries, is likely to come in turn the 

 solution of the hitherto insolvable mystery of the consti- 

 tution of matter. Without doubt the multitudinous facts 

 of mineralogy assembled during the past century by the 

 painstaking investigation of a large number of scientists 

 are destined to play a large part in the solution of this 

 problem. Further, it does not seem too bold a prophecy 

 to suggest, that the time will come when it will be possi- 

 ble to assemble all these unorganized facts that we know 

 about minerals into a harmonious whole and that we shall 

 be then able to formulate the underlying and fundamental 

 principles upon which they all depend. These are the 

 great problems for the future of mineralogical inves- 

 tigation. 



