nf certain inflammable gaseous Compounds. 207 



these flames was ascertained by a comparison of shadows. Under 

 these circumstances, the consumption of gas was found = 640 

 cubical inches per hour, or 0,37 cubical feet. When the same 

 burner was used with oil gas, it consumed 800 cubical inches per 

 hour, or =0,47 cubical feet. 



3. I now employed an Argand burner, with a cylindrical glass, 

 constructed in the usual way, with 12 holes each of the same di- 

 mensions as that of the single jet, and forming a circle 0,7 inch 

 diameter. The pressure being 0,5 inch, the flame was so regu- 

 lated as to burn with its full intensity without producing smoke, 

 and its light being measured by a comparison of shadows, it was 

 found equal to ten wax candles. The consumption of gas 

 amounted to 2600 cubical inches, or about a cubical foot and a 

 half per hour. 



If the result of this experiment be compared vvith the above, in 

 which a single jet was used, it will appear that the proportion of 

 hght from a given quantity of gas is increased in a very high ratio 

 by employing many flames near each other, the consumption of 

 the single jet giving a light of one caudle, being =640 cubical 

 inches, whereas the Argand burner gave a light of ten candles, 

 with the consumption not of 640 x 10 cubical inches, but of 

 2600 cubical inclies. It will be remembered, that in the latter 

 the combustion is perfected by a central current of air, rendered 

 more rapid by the glass tube which surrounds the flame. Count 

 Rumford showed some time ago, " that the quantity of light 

 emitted by a given portion of inflammable matter in combustion, 

 is proportional in some high ratio to the elevation of tempera- 

 ture, and that a lamp having many wicks very near each other, 

 so as to communicate heat, burns with infinitely more brilliancy 

 than tiie Argand lamps in common use*." The construction 

 of the gis Argand burner is particularly calculated to produce an 

 effect of this kind ; and to such a cause the great increase of 

 light relative to the consumption of gas may probably be attri- 

 buted. 



4. The gasometer being filled with oil gas, an Argand burner, 

 giving the light of eight wax candles, was found to consume 

 3900 cubical inches per hour ; and the same intensity of liglit was 

 produced bv tiie same quantity of artificial oil gas; that is, of a 

 mixture of tiiree parts of olefiant and one of hydrogen. 



5. The apertures of burners for coal gas require to be consi- 

 derably larger than those for olefiant or oil gas. In the burner 

 employed in the following experiments, each hole was ^^ inch 

 diameter, and the circle upon the circumference of which they 

 were placed, was 0,9 inch diameter. The light of the flame was 



* Davy'.* Elements of Chemical Philosophy, p. 224. 



found 



