612 THE POPULAR SCIENCE MONTHLY. 



scope we see a world completely hidden from the more powerful 

 eyesight of antiquity. By means of the telescope we study a mul- 

 titude of distant worlds about which the Indian can not even 

 speculate. 



Stentor lived on the banks of the Bosporus, not in a busy 

 American seaport. The modern Stentor, with less perfect throat 

 and lung and ear, speaks through telegraph and telephone across 

 oceans and continents ; and, in the phonograph, talks without re- 

 gard to time or place. 



One's first impression, then, of man's decrepitude must needs 

 be modified. The evolution of power in matters purely physical 

 is undeniable. In spite of this increase of power, however, the 

 modern man is in many ways a poor creature and unlovable. It 

 is an increase of power by deputy. With his narrow chest, dull 

 ears, near-sighted eyes, and squeaky voice, even his multitudinous 

 apparatus fails to make him comparable with the glorious creat- 

 ure who represented the best product of Greek culture. If our 

 reflection ended here, even Mr. Spencer's very clever suggestion 

 would scarcely make us thankful for an evolutionary process 

 which had given us such doubtful progress. There has been an 

 unquestionable falling off of personal power. The advance has 

 been of the race. But we may believe without undue optimism 

 that this failure of the individual will be but temporary. It is a 

 period of acquisition. We may reasonably hope that this will be 

 followed by a period of expenditure, when the gains of the race 

 will be utilized. To-day, the majority busies itself with the 

 means of living ; to-morrow, it may find time to live. The facul- 

 ties have been sacrificed to the demands of research and mental 

 activity. When these have yielded their harvest, we may look 

 for a wholesome reaction upon the faculties themselves. The 

 knowledge which cost a human life, once gained, will serve a 

 thousand lives. The philosopher whose bent form and bleared 

 eyes bespeak research will be succeeded by a more beautiful gen- 

 eration who utilize his discoveries. Any smaller result would 

 hardly justify the current martyrdom. The coming renaissance 

 will be in the fine art of living. 



In this evolution, the materials acted upon have ceased to 

 be simply flesh and blood. The human activity is largely cere- 

 bral, while its materials are inanimate. To supply them the 

 three kingdoms of Nature have been ransacked. It is the pur- 

 pose of the present paper to indicate in a measure the contribu- 

 tions which glass has made to this evolutionary process, for its 

 office is one of increasing importance. In the search for power, 

 the qualities which have given glass so large a value are those 

 particularly of refraction and transparency. These qualities, 

 combined with its hardness and indifference to most chemical 



