INTRODUCTION. 



THERE are many who deplore what they regard as the material- 

 izing tendencies of modern science. They maintain that this pro- 

 found and increasing engrossment of the mind with material ob- 

 jects is fatal to all refining and spiritualizing influence. The cor- 

 rectness of this conclusion is open to serious question : indeed, the 

 history of scientific thought not only fails to justify it, but proves 

 the reverse to be true. It shows that the tendency of this kind of 

 inquiry is ever from the material, toward the abstract, the ideal, the 

 spiritual. 



We may appeal to the oldest and most developed of the sciences 

 for confirmation of this statement. The earliest explanations of 

 the celestial movements were thoroughly and grossly material, and 

 all astronomic progress has been toward more refined and ideal 

 views. The heavenly bodies were at first thought to be supported 

 and carried round in their courses by solid revolving crystalline 

 spheres to which they were attached. This notion was afterward 

 replaced by the more complex and mobile mechanism of epicy- 

 cles. To this succeeded the hypothesis of Des Cartes', who rejected 

 the clumsy mechanical explanation of revolving wheelwork, and 

 proposed the more subtile conception of ethereal currents, which 

 constantly whirled around in vortices, and bore along the heavenly 

 bodies. At length the labors of astronomers, terminating with 



