THE 



POPULAR SCIEICE lOtfTHLY. 



CONDUCTED BYE. L. AND W. J. YOUMANS. 



> The Popular Science Monthly was established a dozen years ago to 

 bring before the general public the results of scientific thought on many 

 large and important questions which could find no expression in the cur- 

 rent periodicals. Scientific inquiry was penetrating many new fields, ex- 

 tending important knowledge, and profoundly affecting 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 sci- 

 entific men of all countries in their bearing upon the higher problems of 

 investigation. Leaving the dry and technical details of science, which are 

 of chief concern to specialists, to the journals devoted to them, The Pop- 

 ular Science Monthly has dealt with those more general and practical 

 subjects 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 as- 

 sured and permanent success. Our Monthly is the acknowledged organ 

 of progressive scientific ideas in this country. Eeceived with favor at the 

 outset, it has gone on increasing in circulation and in influence, until its 

 power is felt and acknowledged in the highest departments of intellectual 

 activity, and its leadership is recognized m 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 con- 

 tinue 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 sci- 

 entific knowledge to be found in any country, and each new volume is cer- 

 tain to prove of increasing interest and value. 



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

 public, individual, social, professional, and industrial. In its irresistible 

 progress it touches everywhere, and affects everybody. It gives law to the 

 material interests 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 new knowledge is rapidly extending, 

 and old errors are giving way, will find that they can keep informed only 

 by subscribing for The Popular Science Monthly. 



Terms : $5.00 per annum, or 50 cents a number ; cloth covers for the 

 volumes, 50 cents each. 



The volumes begin with May and November of each year, and sub- 

 scriptions may begin at any time. 



A club of five will be supplied for $20.00 per annum. 



New York : D. APPLETON & CO., 1, 3, & 6 Bond Street 



594 



