THE 



POPULAR SCIENCE MONTHLY. 



CONDUCTED BY E. L AND W. J. YOU MANS. 



The PoprxAR Science Monthly wns established a dozen years ago to bring 

 before the general public the results of scientific thought on many largo and 

 important questions which could find no expression in the current periodicals. 

 Scientific imiuiry was penetrating many new fieldsi, extending important knowl- 

 edge, and profoundly aflecting opinion upon numberless questions of speculative 

 and practical interest. It was the policy of this magazine at the outset, and 

 has been constantly adhered to since, to obtain the ablest statements from the 

 most distinguished scientific men of all countries in their bearing upon the 

 higher problems of investigation. Leaving the dry and technical details of sci- 

 ence, which are of chief concern to specialists, to the journals devoted to them, 

 The Popclar Science ifoNTnLT has dealt with those more general and prac- 

 tical sabjects which are of the greatest interest and importance to the people at 

 large. 



That which was at first a dubious experiment has now become an assured 

 and permanent success. Our Monthly is the acknowledged organ of progressive 

 scientific ideas in this country. Received with favor at the outset, it has gone 

 on increasing in circulation and in influence, until its power is felt and acknowl- 

 edged in the highest departments of intellectual activity, and its leadership is 

 recognized in the great work of liberalizing and educating the popular mind. 



Making neither sensational appeals nor flaring announcements, we may now 

 refer to its course in the past as a sufficient guarantee that it will continue 

 to discuss in the same earnest and fearless, but always respectful manner, the 

 various important questions falling within its scope that are entitled to the 

 intelligent consideration of thinking people. The twenty-three volumes now 

 published constitute the best library of advanced scientific knowledge to be 

 found in any country, and each new volume is certain to prove of increasing 

 interest and value. 



Science is the great agency of improvement in this ago, private and public, 

 individual, social, professional, and industrial. In its irresistible progress it 

 touches everywhere, and afi*ects everybody. It gives law to the material inter- 

 ests of the community, and modifies its ideas, opinions, and beliefs, so that all 

 have an interest in being informed of its advancement. Those, therefore, who 

 desire to know what is going on in the world of thought in these stirring times, 

 when now knowledge is rapidly extending, and old errors are giving way, will 

 find that they can keep informed only by subscribing for Tue Popclae Science 

 MoNTiaY. 



Terms: $5.00 per Annum. 



Volume XXIV begins with the November number. Subscriptions may begin 

 at any time. 



D. APPLETON & CO., Publishers, 



1, 3. 6c 5 BOND STREET. NEW YORK. 



