5H 



THE POPULAR SCIENCE MONTHLY. 



son, its interest being due not alone to its 

 valuable contents, but quite as much to the 

 form in which they have been put by their 

 illustrious author. When the present Month- 

 ly was started, surprise was expressed in 

 various quarters at the broad scope of its 

 discussions, which it was said went far be- 

 yond the legitimate meaning of our title. 

 Science being considered as a kind of 

 tough and forbidding knowledge belonging 

 to laboratories, observatories, and apothe- 

 caries' shops, popular science was regarded 

 as the same kind of knowledge loosely 

 stated in common language. At the outset 

 we rejected this view as narrow and false, 

 holding that science, instead of pertaining 

 to certain things, consists in a method of 

 knowing, which applies to all things that 

 can be known, and that popular science 

 must be equally comprehensive. Science 

 itself being progressive, its great army of 

 workers is constantly engaged in extending 

 and correcting it by numberless processes 

 of original investigation, while it is the 

 office of popular science to bring its con- 

 clusions, applications, and results, into the 

 sphere of common thought. Learned men 

 long neglected the duty they owed to the 

 public to clothe the result of their labors in 

 authorized and acceptable forms for gen- 

 eral use, and the consequence was that this 

 work was done by incompetent hands, and 

 degenerated into mere amusement and rec- 

 reation ; but, with the progress of liberal 

 opinion, the diffusion of education, and in- 

 creasing respect for the rights and welfare 

 of the people, eminent men of science have 

 turned their attention seriously to the task 

 of embodying their ideas in popular form. 



In his introduction to the present vol- 

 ume, Prof. Tyndall remarks : " One evening 

 during my residence in Berlin, my friend 

 Dr. Du Bois-Reymond put a pamphlet in 

 my hands, remarking that it was the ' pro- 

 duction of the first head in Europe since 

 the death of Jacobi,' and that ' it ought to 

 be translated into English.'" That "first 

 head in Europe " was on the shoulders of 

 Helmholtz, and the pamphlet was his cele- 

 brated essay on the " Interaction of the 

 Natural Forces," which has been exten- 

 sively circulated in this country, and is 

 one of the most elegant and popular expo- 

 sitions of the doctrine of the " Conserva- 



tion of Force " that has appeared in any 

 language. The first complete work of Prof. 

 Helmholtz in English is the volume now 

 issued, consisting of popular lectures on 

 scientific subjects. Speaking of these lect- 

 ures in his preface, the author says : " If I 

 may claim that they have any leading 

 thought, it would be that I have endeavored 

 to illustrate the essence and the import of 

 natural laws and their relation to the men- 

 tal activity of man. This seems to me the 

 chief interest and the chief need in* lectures 

 before a public whose education has been 

 mainly literary." It is gratifying to note that 

 this statement of the chief aim of popular 

 science entirely coincides with the view 

 presented in the prospectus of The Popu- 

 lar Science Monthly. It is not the il- 

 literate that are to be addressed, but the 

 classes that have received such cultivation 

 as the prevailing educational system affords, 

 while the development and illustration of 

 natural laws in their bearing upon the higher 

 nature and elements of man is the ultimate 

 and most important end to be attained. 



Hermann Ludwig Ferdinand Helmholtz 

 was born at Potsdam in 1821. He studied 

 medicine, and was at first military physician 

 and afterward assistant at the Astronomical 

 Museum at Berlin in 1848. From 1849 to 

 1852 he was Professor of Physiology in the 

 University of Konigsberg. He became 

 Professor of Physiology at the University 

 of Bonn in 1855, and in 1858 accepted the 

 physiological chair in the University of 

 Heidelberg. He is now reestablished in 

 Berlin as professor in the university of 

 that city. Prof. Helmholtz has attained a 

 recognized preeminence in three great de- 

 partments of knowledge physiology, phys- 

 ics, and mathematics. He began with the 

 study of physiology, but, finding that to be 

 dependent upon physics, he proceeded to 

 master the physical field. But here, find- 

 ing again that physics depends upon mathe- 

 matics, he pushed on to the conquest of 

 this department of science. His great 

 works are on " Physiological Optics " and 

 " The Physiology of Audition," and, by his 

 thorough acquaintance with physics and 

 mathematics, he has greatly enriched and 

 extended our knowledge of the science of 

 these higher senses. Prof. Helmholtz's in- 

 tellect is characterized by great breadth and 





