SO taimCAL SOUNDS PRODUCED BV HIDKOGEN CA$, 



minifhes their volume. This then is the mod effential condition 



to the production of an intenfe permanent found ; namely, a 



great difference between the temperature of the air and the 



vapour ; and this difference remains always the fame, on ac» 



Not fo In the count of the continual renewing of the air. The fame effect 



does not take place in the tubes with bulbs, and accordingly 



their found is weaker and lefs durable. 



The founds by From the knowledge of this condition, that a great differ* 



Imenfe ?nT ^ ence between the temperature of the air and the vapour is ne- 



warm room filled cetfary to the production of found, it will be eafy to compre- 



with company } j ienc j jj^j. everv c ir € umftance which augments the heat of the 



current of air, and diminifhes that produced by the combuftion 



of the gas, will tend to weaken and even to annihilate the 



kecaufe the air is found of the tube. Thefe two circum fiances are both found 



warmer, and thej n a warm room f^\[ e ^ vvitH company. The current of air in- 



combuftion niri- ,,• * 



weaker for want ftead of being cold is heated, and the quantity of oxigen being 

 of oxigen. j e f Sj t} ie h eat f fa combuftion is lefs. It is not then furprifing 



that in fuch rooms the experiment does not always fucceed. 

 Sounds by phof- Brugnatelli produced founds by the fimple combuftion of 

 phorus. phofphorus in tubes. Some philofophers being perfuaded that 



fonorous effects could only be attributed to hidrogen, were 

 difpofed to infer its prefence in phofphorus. From what we 

 have ftated, it feems more fimple to explain the phenomenon 

 by the production of phofphoric acid in the vaporous form, 

 which becomes itrongly elaftic by means of the caloric difen- 

 gaged during the combuftion, but of which the volume dimi- 

 nifhes by the contact of cold air. We have here the alternate 

 expanfion and contraction neceffary to the production of 

 found. 

 Condufion. Such are the fmall number of obfervations which I have had 



an opportunity to make on the fonorous tubes. I hope that 

 they will intereft fuch as are more particularly engaged in this 

 branch of natural philofophy, and tend to direct their attention 

 to a curious fact which has not hitherto been fufficiently exa- 

 mined. 



ANNOTATION.— W. N. 



That aqueous AS the fundamental effect in this very ingenious expla- 

 vapour is con- nation (namely, that aqueous vapour is condenfed with 

 grew rapidity ; extreme rapidity), may not appear to fome readers to be 



fo 



