TRANSMISSION OF SOUND THROUGH LONG TUBEI. Jlf^l 



were th^ objects of the following experiments. Some of 



them were made by Mr. Bouvard and me, others by one of 



MS nlone. Mr. Malus, colonel of engineers, was likewise 



present at many of ihem. In all of them we were assisted 



by Mr. Martin, maker of nautical watches, a very ingenious 



and attentive artist, who was particularly appointed to give 



instantaneously, at determinate seconds, the stroke that 



was to produce the sound. 



The sodorous body, on which we operated, was formed by wliich consist 



miseries of cylindrical tubes of cast iron, of as equal (Ji- ^'^'* ^^'''®* P'^ 



. . . . >i'on pipes. 



mensions as possible, and the mean length of which I found 



lobe ys 15 met.* [8 feet 3 in. nearly]. This I found by mea- 

 suring the whole length of twelve cylinders placed end '^o end. 

 The tubes nve separated by leaden rings covered with 

 tarred fustian: but they are pressed together by strong 

 screws, so that the rings are forcibly compressed, and so 

 close a contact produced, that no water can escape. The 

 mean tiiickaess of each ring is 0'014286 met. [0*56-2 of 

 an inch], as 1 found by measuring twelve. The whole series 

 of cylinders forms a curved line, which has two inflexions 

 about the middle of its length : but they were not all joiued 

 together at once, and we made our experiments on different 

 successive lengths, as will be seen in my report of them. 



The first were made by Mr. Bonvard and myself' on 78 Istsetofeip*. 

 cylinders, forming a length of 196* 17 met., to which must [o^Jt'h of 2" * 

 be added 1-1 for the 77 rings, giving a total length of yards. 

 197*27 met. [21 5-587 yds]. The following were the phe^ 

 nomena weobserted. 



In the last cylinder was placed a ring of iron, of the Apparatas. 

 same diameter as the cylinder, and having in its centre a 

 bell without a clapper, and a hammer thqt could be let 

 fall at will. The hammer, as it struck the bell, struck also 

 the cylinder, with which it formed a communication by 

 means of the iron ring. Two soi^nds must therefore be 

 heard, one transmitted by the Cylinder, the other by the air. Mode of e*. 



In fact they weve heard very distinctly by applying the perimentintg. 

 ear to the cylinder*j and even vvithout this. They appeared 



" *' All the measures feVnployed in this paper are expressed in metres; 

 <in4 the tiroe in seconds of the sexagesimal division, 



sensibly 



