a2 INTERPRETATIONS OF NATURE. 
would embrace the known facts relating to heat, light, 
electricity, and magnetism. Then also came the deduc- 
tion of those universal laws known as the correlation 
and conservation of energy. 
The outlines of the earth’s surface had been sketched 
by the navigators of the fifteenth and sixteenth centu- 
ries, but the history of its structure remained unknown. 
There was no one who could read the record of the 
rocks, or describe the method by which its valleys had 
been dug, its mountains raised, and its architecture 
made so grand and beautiful. The pictured forms of life 
upon the stone—Whence came they? What are they / 
By what cunning device did nature’s brush paint them, 
or her burin engrave them, or her chisel carve these 
forms so real and life-like? How came these casts of or- 
ganic things, arranged with special types in special 
places, and what is the chronological order of events ? 
Tt was not until the early part of the present century 
that any systematic effort was made to interpret any of 
these things. Theories there were, but they had no 
basis in facts, and reflected only the troubled dreams of 
the astrologer who, displaced from the heavens by the 
telescope, found for a time a hiding place in the recesses 
of the rocks, and in the caverns of the earth. Within 
the short period of half a century the increase of geo- 
logical knowledge has revealed the mysteries of the 
earth and told the story of its creation. 
The revelation of truth thus ‘‘gathered from one 
small sphere, is the deciphered law of all spheres,” and 
evidence is given that the principle upon which rests the 
interpretation of all physical phenomena, is matter af- 
fected by the uniform and constant operation of cosmic 
forces. 
Notwithstanding the progress made in accumulating 
and generalizing the facts relating to animal life, our 
