EDITOR'S TABLE. 



845 



cies that is so adequate and practical as 

 this annual gathering of scientific men 

 in the different cities, and under the 

 conditions secured by the American 

 Association. 



The problem of its success is one of 

 social dynamics. There are resistances 

 to be overcome in the shape of difficul- 

 ties in bringing scientific men together 

 from distant points, and of public apa- 

 thy toward the interests of science. 

 The American Association has been 

 checked by these impediments, but it 

 has made headway in spite of them. 

 There has been a varying success at its 

 different meetings, but on the -whole 

 the most encouraging progress, which 

 is signalized by the fact that the last 

 meeting has been the most successful 

 and satisfactory of all. 



We print the able and interesting- 

 address of the retiring President, Dr. 

 George F. Barker. It is a model dis- 

 course of its elass, reporting the pres- 

 ent state of knowledge upon a subject 

 of grave interest, and in a style suited 

 to all readers of general intelligence. 



Dr. Lewis H. Morgan, of Bochester, 

 presided with an easy dignity over the 

 general sessions of the meeting, and he 

 could not fail to be gratified witli the 

 increasing interest shown in the ethno- 

 logical studies to which he has so long 

 devoted himself, and of which he is 

 now the most eminent American rep- 

 resentative. The section dealing with 

 these subjects had many instructive pa- 

 pers and a full attendance throughout 

 the meeting. 



Professor George J. Brush, of New 

 Haven, was elected the next President, 

 and will .preside over the meeting to be 

 held at Cincinnati, beginning August 

 17, 1881. 



THE XEW PriOTOPIIOXE. 



TnE most striking result brought 

 out at the late meeting of the American 

 Association had reference to the rela- 

 tions of sound and light, and was due 



to the joint labors of Mr. A. Graham 

 Bell and Mr. Sumner Tainter, of Bos- 

 ton. The luminous ray, whether of 

 sunlight or from an artificial source, was 

 shown to be capable of transmitting 

 articulate sounds, as the wire transmits 

 them in the case of the telephone. The 

 mechanical combination by which this 

 effect is produced is called the }>hoto- 

 plione. We print in full Mr. Bell's pa- 

 per describing the principle and mechan- 

 ism of the contrivance, and the experi- 

 ments by which it was elucidated and 

 brought into shape. The metal sele- 

 nium, discovered in the early part of 

 the century, but hitherto of no practi- 

 cal use, here comes into prominence. 

 It was known to have curious proper- 

 ties, shifting into allotropic forms with 

 the most contrasted characters, and 

 changing its electrical relations in a re- 

 markable manner under the influence of 

 light. Under the arrangements of the 

 inventors, rays of light give rise to sound 

 by impinging upon a surface of seleni- 

 um sounds which are audible through 

 the telephone either as continuous mu- 

 sical notes of different pitches, or as 

 vocal communications. Though it is 

 said that light produces the effect, yet 

 this is not strictly true; for a thick 

 plate of India-rubber, if interposed in 

 the path of the acting beam, intercepts 

 all the light but still permits the pas- 

 sage of the radiant force which pro- 

 duces the sound. It is some dark ray 

 accompanying the light proper that does 

 the work. The experimenters have 

 found also that other substances share 

 with selenium the property here made 

 available, though in a less degree. We 

 thus have another step in the rapid 

 progress of molecular physics and the 

 marvelous interaction of forces which 

 is sure to stimulate experimental inqui- 

 ry, though whether it will confound 

 past conclusions and clear up past mys- 

 teries it is impossible to say. And 

 equally impossible is it to say whether 

 the photophone will turn out to be of 

 any practical use. But it is certainly 



