No, G.] president's address b. a. a. s. 337 



ralogy of the eommenceuient of the period over whicli we have 

 so hastily gianced. Then the study of minerals was confiued 

 almost exclusively to their external characters. Led by Werner, 

 and reinforced by his most gifted pupil, Mohs, the majority of 

 mineralogists claimed mineralogy to be a purely natural history 

 science. They gave their attention, as has been well said, en- 

 tirely to "how tlie mineral looked," and not at all to "what it 

 was." On the other hand the development of analytical chem- 

 istry by the labors of Klaproth and Berzelius led many to take 

 up mineralogy from a purely chemical stand-point. These two 

 schools working independently brought great confusion into the 

 science. The discoveries of Haiiy in crystallography, and espe- 

 cially his labors in establishing a mathematical foundation for 

 the geometrical form of crystals, and the recognition that the 

 constancy of form depended on the constancy of the " integrant 

 molecule," were steps which paved the way for modern mineral- 

 ogy. In this a union of all the physical, geometrical, and chemi- 

 cal properties is required in order to determine the true character 

 of a mineral. Further, we are called upon to investigate the 

 history of its origin, its relation to associated species, the changes 

 which it undergoes, and the causes and results of these changes. 

 Here we have to do largely with both geology and chemistry. 

 From this it becomes evident that a much broader foundation is 

 now required for the mineralogist than in the early days of the 

 century. The bearing of physics, geology and chemistry in the 

 study of the mineral kingdom must be thoroughly recognized 

 and appreciated by every investigator who desires to contribute 

 to further progress. No mineralogist can expect to have a pro- 

 found knowledge in all these directions, but he must be at least 

 capable of intelligently applying to his subject the results ob- 

 tained by experts in these sciences. Mineralogy is deeply 

 indebted to special investigators in all these departments. With- 

 out their co-operation it would have been impossible to discover 

 the relations of form and other physical characters with that 

 fundamental arrangement of molecules whose nature it is now 

 admitted controls all the properties of a substance. The study 

 of natural crystals has afforded rich material for the physicist. 

 In the department of optics it has given results from which many 

 fundamental laws have been deduced ; and natural crystals, too, 

 have furnished, in many cases, the very apparatus which made 

 investigation possible. Some chemists claim that mineralogy is 

 Vol, X, V 2 No, (J. 



