322 



SCIENCE. 



[N. S. Vol. XVI. No. 400. 



movement of the solai' system among other 

 systems. If it were possible for one to fix 

 in space coordinates by which to measure 

 these various motions, the movement of an 

 air particle, of a water drop, of a mineral 

 grain, would be seen to be extraordinarily 

 complex. 



It is clear that there' is every reason to 

 believe that no atom or molecule in the 

 world ever occupies the same absolute posi- 

 tion in space at any two successive 

 moments. Indeed, it must have been an ex- 

 traordinary accident, if it ever . has oc- 

 curred, that a single particle has occu- 

 pied in all the history of the universe 

 exactly the same position that it has oc- 

 ■cupied at any previous time. No such 

 thing as rest for any particle of matter 

 anywhere in the earth or in the universe is 

 known ; but, upon the contrary, everywhere 

 'all particles are moving in various ways 

 with amazing speed. 



. No science is independent of other sci- 

 ences, but geology is peculiar in that it is 

 based upon so many other sciences. As- 

 tronomy is built upon mathematics and 

 physics. Chemistry and physics to a con- 

 siderable degree are built upon each other. 

 Physics also requires mathematics. Biolo- 

 gy demands a limited knowledge of physics 

 -and chemistry. However, it cannot be said 

 that a knowledge of the basal principles 

 of more than one, or at the most two, other 

 sciences is an absolute prerequisite for a 

 successful pursuit of astronomy, chemis- 

 try, physics or biology. This is not true of 

 geology. In order to go far in general 

 ■geology one must have a fair knowledge 

 of physics, chemistry, mineralogy and biolo- 

 gy. These may be called the basal sciences 

 -of geology. In certain lines of geology 

 the additional sciences, mathematics, as- 

 tronomy and metallurgy, are very desirable. 

 • Geology treats of the world. In order to 

 have more than a superficial knowledge of 

 geology, it is necessary to know about 



the elements which compose the world; 

 how force acts upon these elements; what 

 aggregates are formed by the elements and 

 forces, and how life has modified the 

 construction of the world. Chemistry 

 teaches of matter; how it is made up, 

 both in life and in death. Without 

 an understanding of its principles we 

 cannot have an insight into the consti- 

 tution of the earth or of any part of it. 

 Physics teaches of the manner in which 

 the many forms of that strange something 

 we call force acts upon matter. Without 

 a knowledge of its principles we can never 

 understand the transformation through 

 which the world has gone. The elements 

 which compose the earth under the laws of 

 physics and chemistry aggregate into those 

 almost lifelike bodies which we call miner- 

 als. The minerals are commingled in vari- 

 ous 'ways' in the rocks.' Without a knowl- 

 edge of mineralogy no one can have even a 

 superficial understanding of the constitu- 

 tion of rock masses. Biology teaches of the 

 substances alive which clothe the outer part 

 of the earth. Life is one of the most funda- 

 mental of the factors controlling the geo- 

 logical transformations in the surflcial belt 

 of weathering; it has acted as the greatest 

 precipitating agent in the sea. Life, has 

 had therefore, a profound and far-reaching 

 effect in determining' the nature of the 

 sedimentary formations. 



The sciences of chemistry, physics and 

 biology have been built up by using minute 

 parts of the materials of the earth. If 

 geology, or a science of the earth, is to be 

 constructed, it must apply to the earth as a 

 whole the principles which have so en- 

 lightened us as to the nature and relations 

 of the fractions of the earth which we 

 observe and handle in our laboratories of 

 physics and chemistry and biology. 



It thus appears that geology is a com- 

 posite science; and it might in a certain 

 sense be called an applied science. Indeed 



