Dr. A. M. Mayer on a New Lantern- Galvanometer. 25 



mined by the comparative anatomist, no biological researches, 

 no microscopic investigations, no considerations regarding natu- 

 ral selection or the survival of the fittest can solve the great 

 problem of nature ; for it lies in the background of all such in- 

 vestigations. The problem is molecular. From the hugest 

 plant and animal on the globe down to the smallest organic 

 speck visible under the microscope, all have been built up mole- 

 cule by molecule ; and the problem is, to explain this molecular 

 process. If one plant or animal differs from another, or the 

 parent from the child, it is because in the building-up process 

 the determinations of molecular motion were different in the two 

 cases; and the true and fundamental ground of the difference 

 must be sought for in the cause of the determination of mole- 

 cular motion. Here in this region the doctrine of natural selec- 

 tion and the struggle for existence can afford no more light on 

 the matter than the fortuitous concourse of atoms and the ato- 

 mical philosophy of the ancients. This, I trust, will be rendered 

 still more evident when we come to examine in detail the argu- 

 ments advanced by modern evolutionists in support of their 

 fundamental hypothesis, " that the whole world, living and not 

 living, is the result of the mutual interaction, according to 

 definite laws, of the forces possessed by the molecules of which 

 the primitive nebulosity of the universe was composed." 



II. On a new Lantern- Galvanometer. By Alfred M. Mayer, 

 Ph.D. J Professor of Physics in the Stevens Institute of Tech- 

 nology j Hoboken, N. J., U.S. America^. 



ON the 21st of December, 1871, I delivered a lecture on 

 Magnetism before the American Institute at the Academy 

 of Music in the city of New York. It was necessary for the 

 experimental discussion I then made of the earth's magnetism 

 to use a galvanometer so constructed that the deflections of its 

 needle would be visible to a large audience ; at the same time 

 the astatic condition of this needle had to be so controlled that 

 it could readily be altered during the progress of the lecture; 

 while, finally, the arrangement of the damping-magnets had to 

 be such as allowed me instantly to bring the needle into the 

 magnetic meridian when disturbed therefrom whenever I set in 

 action the huge electromagnet used on that occasion. Indeed 

 one of the principal uses to which this galvanometer was applied 

 in the lecture was the exploration of the magnetic condition of 

 the space surrounding this electromagnet. This I accomplished 



* From the American Journal of Science for June 1872. Communicated 

 by the Author. 



