2(> MUSICAL SOUNDS PRODUCED BY HIDROGEN GAS. 



heat ; that of a lamp with alcohol is commonly fufficient ; but 

 the flame muft be large and ftrong when the tube is large. 

 After the tube has been thus expofed for a few feconds, the 

 found is heard. Thofe tubes whofe diameters are confiderable 

 give a deep found, and the fize of the bulblikewife feemsalfo 

 to contribute to the fame effect : the found continues for feveral 

 feconds, and then gradually decays, and at length entirely 

 ceafes. By fuffering the apparatus to cool, and caufing the 

 condenfed liquid to defcend into the bulb, the experiment may 

 be repeated as often as (hall be thought neceflary. 

 Investigation of Such is the experiment by means of which I think the phe- 

 koth kinds of nomenon of the mufical tubes may be fatisfa&orily explained. 

 Let us firft examine what pafTes in the tubes with bulbs, with 

 the eflential conditions under which they produce their found, 

 and then endeavour to difcover the caufe. I will then com- 

 pare it with the found produced in tubes with hidrogen, and 

 enquire in what refpecls the effects produced by thefe two in- 

 ftruments refemble one another, with the differences they pre- 

 fent, and the caufe of thofe differences. 

 Conditions for The conditions eflential to the production of found in tubes 

 the tube and with bu j bs are ^ ^ Th at the tube fa^d have a bulb. I 

 There muft be a never could excite fonorous vibrations in a tube (imply doled 

 feuto i at one end. 2d, This bulb muft contain an evapourable liquid, 



containing wa- Water fucceeds very well, but it has this difadvantage j it 

 ter » forms, in pafling from the vapourous to the liquid (late, a drop 



of water in the tube, which often completely obftru&s it ; and 

 at other times, by running along the warm part of the glafs, it 

 or rather mer- frequently breaks it. Mercury has not this inconvenience : I 

 curv > never could fucceed in producing founds with ether, alcohol, 



alcohol, or fulph. or concentrated fulphuric acid. The founds are influenced by 

 acid. the quantity of liquid contained in the bulb. It fhould be as 



l>e very 'fmaU in frnall as poffible. If there be too much, the vapour fills the 

 quantity. tube, and by completely expelling the air, renders it equally 



warm throughout, and no found can then be produced. 3d, 

 The heat muft The third condition eflential to the fuccefs of this experiment, 

 be ftrong, to the j s the application of a ftrong heat to the bulb while the reft of 

 and the tube tne tuDe continues cold ; for if there be not a marked differ- 

 kept cold. ence in the temperatures of the tube and of the bulb, no fono- 

 There muft be rous eflfeft will take place. Mh, The prefence of atmofpheric 

 feme air m the a j r ; n t he tube is indifpenfable; if it be entirely excluded, no 

 effeft will be produced ; and in every ftage of the experiment 



it 



