234 



THE POPULAR SCIJENCE MONTHLY. 



sound, and we cannot expect it, " when 

 further developed by study, to do for us, 

 with regard to faint sounds, what the mi- 

 croscope does with matter too small for 

 human vision." 



We cannot correctly regard the sound 

 heard in the telephone receiver as " a mag- 

 nified image " of the original vibrations ; 

 for, while the fundamental tone is repro- 

 duced with considerable accuracy, the har- 

 monics or overtones, giving the timbre, or 

 individuality to the sound, are in most 

 cases very imperfectly rendered. 



2. If the ear is placed in as favorable 

 a position to hear the original faint vi- 

 brations (which jar the delicately-poised 



piece of carbon) as it is when listening to 

 the telephone, it will be found that the in- 

 creased volume of sound issuing from the 

 diaphragm of the receiver is more imaginary 

 than real. 



For these, and other reasons, the writer 

 is of the opinion that the probable future 

 value of this discovery has been greatly 

 exaggerated, and that it is likely to prove 

 an addition to the rather plentiful crop of 

 scientific green fruit which fails to ripen 

 into the full perfection so enthusiastically 

 predicted by the luxuriance of the blossoms. 

 Respectfully yours, 



A. E. OUTERBRIDGE, Jr., 



Assay Laboratory U. S. Miut, Philadelphia. 



EDITOR'S TABLE. 



ELECTRIC ILLTIMINATION. 



"^rOTIlING is more natural than that 

 -1-^ there should be great expectations 

 in the non-scientific mind in regard to 

 what electricity is destined to do for the 

 world in future — expectations which, on 

 the one hand, are grounded in reason, 

 and, on the other, are liable to the most 

 extravagant exaggeration. The mar- 

 velous things already accomplished by 

 means of this mysterious agent, as made 

 familiar in the electro-chemical indus- 

 tries, the telegraph, telephone, and elec- 

 trical illumination, have a tendency, of 

 course, to prepare the mind to look for 

 further unusual and astonishing results. 

 Just now a revolution in illumination is 

 widely anticipated, by which the com- 

 mon illuminants will be superseded in 

 the daily life of the people, through 

 improvements in the electrical light. 

 The probability of this important re- 

 sult is greatly increased, and is, indeed, 

 supposed to have become a certainty, 

 because electrical illumination is al- 

 ready an established fact on a large 

 scale, it having been used in light- 

 houses for years, and successfully in- 

 troduced into factories, depots, thea- 

 tres, and other places where large spaces 

 are to be illuminated. So much — the 

 main thing, and apparently everything 

 —being actually gained as a fact of 

 experience, the carrying out of the 



invention into minor details is taken 

 as a foregone conclusion. In this state 

 of the public mind the announcement 

 of Mr. Edison — the foremost inventive 

 genius of the age — that he had actually 

 solved the problem which would make 

 electric illumination available for com- 

 mon household uses, was generally ac- 

 cepted as a matter of course, and sent 

 a tremor through the gas-stocks of the 

 world. Nevertheless, the desideratum 

 has not yet been reached, and, for 

 aught that actually appears, we are no 

 nearer this important consummation 

 than we were twenty years ago. 



It may be well to remind the san- 

 guine believers in this unquestionably 

 most desirable improvement, of the 

 analogous excitement there was, some 

 thirty or forty years ago, in regard to 

 electricity as a motive power. A new 

 source of mechanical energy had been 

 discovered in electro-magnetism, which 

 was developed by appropriate ma- 

 chinery, so as to be capable of doing 

 all kinds of work. There was the ac- 

 complished fact, and buzz-saws were 

 driven through two-inch planks, before 

 astonished audiences, merely by bat- 

 teries in the cellar, connected with the 

 working-machine by conducting wires. 

 The steam-engine was threatened, and 

 we seemed to be on the eve of a new 

 epoch in the use of motive powers. 



