NATUEAL PHILOSOPHY. 163 



tions of the aerial pen were so delicate that if any appreciable force 

 were required to effect the transcription, the resistance would at once 

 stop all movement. This difficulty was at last overcome by employ- 

 ing a strip of thin paper, upon which was deposited a film of lamp- 

 black obtained from the smoke of burning bodies. This sensitive sur- 

 face is carried along by clockwork agency, in front of the vibrating 

 style, so that the successive movements of the latter shall not impinge 

 one on the other, when the result is a series of lines written on the 

 paper, composed of the most complicated systems of curves, and form- 

 ing a natural autograph of the producing sounds. 



Of course it will be understood that the above is intended more as 

 a brief outline of the principle of M. Scott's instrument than as an 

 exact description of its individual details. In reality, especially in 

 the one recently made, it is far more complicated than would be im- 

 agined from this brief sketch ; but the phonographs produced by it are 

 marvellously perfect. Every separate source of sound has an individ- 

 uality of its own. The sounds of different musical instruments, for 

 instance, are easily distinguished from one another, and from the hu- 

 man voice. This latter, moreover, gives different traces, according to 

 its character the sweet, soft voice of a female, especially when sing- 

 ing, being characterized by great beauty and harmony in the curves 

 impressed on the paper ; in those produced by the harsher voice of a 

 man, the curves are larger and more rugged-looking ; whilst in a 

 shriek or a shout, or in the harsh, discordant sounds of instruments, 

 the waves are irregular, unequal, and broken up into secondary 

 vibrations of all degrees of amplitude. 



An oration, delivered with varying rapidity, and with the pitch of 

 the voice greatly modulated in different parts, has a very striking ap- 

 pearance in its phonograph. Rapidly-spoken parts have the curves 

 crowded together, whilst in others they are widely separated. The 

 loud tones of the voice are shown by the written waves rising to per- 

 haps half an inch or more in height, whilst the low tones are not more 

 than the eighth of an inch high. The modulations of the voice are thus 

 shown very beautifully by the varying height of what may be called 

 the letters of sound. 



The fact of being able to make spoken sounds record themselves 

 permanently on paper is of itself most singular and astonishing ; but 

 if it is ever developed, as the inventor says it shortly will be, to suffi- 

 cient perfection to enable it to take down speeches, which may be 

 written off verbatim, it is difficult to imagine the importance of the 

 discovery, whether it be in respect to the unimpeachable accuracy 

 of the process, the entire absence of trouble and expense in reporting 

 any articulate sounds, or the great saving of the time and the exhaust- 

 ing labors of reporters. 



ACOUSTICS ESr BUILDING. 



In a paper on the above subject read before the Institute of British 

 Architects, by Mr. T. R. Smith, the author, after referring to the ex- 

 periments of M. Biot on the transmission of sound through a pipe one 

 thousand yards long, through which a whisper was distinctly audible, 

 and to the curious exception discovered by Mr. Scott Russell to the 



