24 Tube's rendered harmonious by Hydrogen Gas. . 



Confequeutly, by fuppreffing from the colours of hard 

 porcelain the carmine of goM, which is not indifpen^aljly, 

 neceflarv, we (liall have a fcries of colours which do not 

 change, and which will be abfclutely fimiiar to thole pre- 

 fented to the Inditute in the year 6. 



IV. Memoir on Tubes rendered harmonious by Hydrogen Gas. 

 Read before the Society of Fhyjics and Natural HiJIory of 

 Geneva^ by G. Delarive, Ex-Fre/ident of the Royal 

 Society of Edhiburghj and Member of the Medical Col- 

 leges oj London and Geneva *. 



I 



N a former fitting, our learned colleague profeflTor Pi(!^let 

 communicated to tlie fociety a ieries of refearches on tubes 

 rendered harmonious by means of hydrogen g:-.-, and ex- 

 plained the different niufical phaen -mena to which thcfe 

 tubes give birth. He pointed out the influence of the length 

 of the tube; of its breadth, and of the place where the gas 

 is burnt ; and explained the nature of the founds produced. 

 In regard to the eaufc of the found, he offered only conjec- 

 tures : as hi? labour was not dlre£led to that objeft, it is 

 under this point of view that I have refumed it. 



Profcffor Brugnatelli, in my opinion, is the firfl perfon 

 who publiflied the experiment ; which I fl)all endeavour to 

 explain. It had been invented by a German : I (hall here 

 give a view of the princii.a! circumttances attending it. 



If a current of inflanitc. hydrogen gas be introduced into a 

 tube the fubftance of which is elaltic and fonorous, fuch as 

 glafs, metal, dry wood, &c., this tube, after the interval of 

 ibme feconds, will emit a harmonic found : if it be open at 

 both extremities, the found will be ftrong and full. 1 he ex- 

 periment may, however, fucceed with a tube clofed herme- 

 tically at one end, provided its diameter be fo large as to ad- 

 mit of a circulation of li.c atmofpheric air in fufficicnt quantity 

 to rr;aintain the combudion of the gas. The conditions ef- 

 fentiallv neccflary for this purpofe are : ift, That the fub- 

 ftance of the tube be elaftic, proper for producing an echo; 

 that is to fav, for rcfleAing the undulations which proceed 

 from the fonorous )K)int: a tube of paper or padcboafd will 

 emit no found, ad, The flame mufl be produced by a cur- 

 rent of hydrogen gas. An inflamed jet of the vapour of fpirit 

 of wine or ether, a lighted taper, &c. are incapable of making 

 the tube emit any found. 



* From the Journal de Ph\i/iqiie, Frudlidor, an. i o. 



Let 



