52 



SCIENTIFIC NE\VS. 



[Jan. 20, rSSS. 



receiving diaphragm is placed in the position of use, and 

 as the wax cylinder revolves, the diaphragm is vibrated 

 by the sound waves, thus moving the needle so as to 

 cause it to cut into the wax cylinder and produce indenta- 

 tions which correspond to the movements of the dia- 

 phragm. After the record is made, the carriage is again 

 returned to the point of starting, the receiving diaphragm 

 is replaced by the speaking diaphragm, and the carriage is 

 again moved forward by the screw, as the cylinder 

 revolves, causing the point of the speaking diaphragm to 

 traverse the path made by the recording needle. As the 

 point of the curved wire attached to the diaphragm 

 follows the indentations of the wax cylinder, the speak- 

 ing diaphragm is made to vibrate in a manner similar 

 to that of the receiving diaphragm, thereby faithfully 

 reproducing the sounds uttered into the receiving mouth- 

 piece. 



A crucial test of the capabilities of this machine 

 was recently made at Mr. Edison's laboratory, near 

 Llewellyn Park, Orange, N.J. A paragraph from 

 a morning newspaper was read to the machine in our 

 absence, and when upon our return to the instrument it 

 was reproduced phonographically, every word was 

 distinctly understood, although the names, localities, and 

 the circumstances mentioned in the article were entirely 

 new and strange to us. Another test of the perfection of 

 the machine was the perfect reproduction of whistling 

 and whispering, all the imperfections of tone, the half- 

 tones, and modulation even, being faithfully reproduced. 

 The perfect performance of the new instrument depends 

 upon its mechanical perfection — upon the regularity of 

 its speed, the susceptibility of the wax cylinder to the 

 impressions of the needle, and to the delicacy of the 

 speaking diaphragm. No attempt is made in this in- 

 strument to secure loud speaking — distinct articulation 

 and perfect intonation have been the principal ends 

 sought. The new phonograph is to be used for taking 

 dictation, for taking testimony in court, for reporting 

 speeches, for the reproduction of vocal music, for teach- 

 ing languages, for correspondence, for civil and military 

 orders, for reading to the sick in hospitals, and for 

 various other purposes too numerous to mention. 

 Imagine a lawyer dictating his brief to one ot these little 

 machines ; he may talk as rapidly as he chooses ; every 

 word and syllable will be caught upon the delicate wax 

 cylinder; and, after his brief is complete, he may 

 transfer the wax cylinder to the phonograph of a copyist, 

 who may listen to the words of the phonograph and 

 write out the manuscript. The instrument may be 

 stopped and started at pleasure, and if any portion of the 

 speech is not understood by the transcriber, it may be 

 repeated as often as necessary. 



In a similar manner a compositor may set his type 

 directly from the dictation of the machine without the 

 necessity of " copy," as it is now known. Mr. Edison 

 informs us that the whole of " Nicholas Nickleby" could 

 be recorded upon four cylinders, each 4 in. in diameter 

 and S in. long, so that one of these instruments in a pri- 

 vate circle, or in a hospital, could be made to read a 

 book to a number of persons. This is accomplished by 

 means of a multiple earpiece. 



The little wax cylinders upon which the record is 

 made are provided with a rigid backing, and the cylin- 

 ders are made in different lengths, the shortest — i in. 

 long — having a capacity of 200 words, the next in size 

 400 words, and so on. These cylinders are very hght, 

 and a postal-case has been devised which will admit 



of forwarding the cylinders as readily as letters are now 

 posted. The recipient of the cylinder will place it on 

 his own phonograph and listen to the phonogram, in- 

 which he will not only get the sense of the words of the 

 sender, but will recognise his expression, which will, of 

 course, have much to do with the interpretation of the 

 true meaning of the sender of the phonogram. 



A very interesting and popular use of the phonographi 

 will be the distribution of the songs of great singers, 

 sermons, and speeches, the words of great men and 

 women, music of many parts, the voices of animals, etc., 

 so that the owner of a phonograph may enjoy these- 

 things with little expense. 



It may even be pressed into the detective service, and' 

 used as an unimpeachable witness. It will have but one 

 story to tell, and cross-examination cannot confuse it. 

 Extensive preparations for the manufacture of the pho- 

 nograph have been made, and it is probable that within 

 a short time these instruments will be as common and 

 as indispensable as the sewing-machine or the type- 

 writer. — Scientific American. 



THE BACTERIOLOGICAL WATER- 

 TEST. 



DR. G. BISCHOF, F.C.S., has recently communicated- 

 to the Royal Society the results of an extensive 

 series of experiments on this subject. 



His researches, which have been performed with 

 special reference to that vexed question, the metropolitan 

 water supply, lead him to the following conclusions : — - 



No bacteriological water-test can satisfy the demands; 

 of hygiene unless it is qualitative, distinguishing be- 

 tween harmless and pathogenic microphytes. No such 

 test is at present known. 



Merely numerical results without such distinction are 

 entirely unintelligible, unless the time and other condi- 

 tions of culture of each test be specified. 



A small portion only of the "colonies" capable of 

 growing in gelatine-peptone is indicated by three days' 

 culture. The ratio of "colonies" thus indicated by 

 three daj's' culture to that of the total present appears to 

 differ so widely in different samples that the number of 

 colonies obtained from them cannot be compared with' 

 each other. 



Instead of attempting any such comparison, the changes- 

 taking place from time to time should be followed up. in^ 

 each sample separately. 



Extension of culture beyond three days increases the- 

 trustworthiness of the results ; how far this holds good,, 

 and how far culture should be extended, we have at 

 present not sufficient evidence to show. 



The usefulness of results is probably still further in-- 

 creased by combination and extension of culture with 

 storage in sterilised flasks for a certain time. As regards 

 the control of the working of sand-filtration at water- 

 works, any bacteriological test, to be of practical utility, 

 should be repeated at intervals certainly not exceeding a 

 fortnight. It is desirable for the purpose of such con- 

 trol to test the water entering and leaving each filter. 



Electric Microscope. — We learn that Professor 

 Waldeyer, of Berlin, is having an electric microscope 

 constructed in Vienna for electric light demonstrations. 

 We presume this instrument is to take the place once 

 occupied by the solar microscope. 



