244 On Mf.Ricardo's comparatiuc Advaiitages 



Brande's train of reasoning is a little fallacious;" and as to his 

 arithmetic, they are (like myself) quite unable to comprehend 

 it. Nevertheless, the points upon which we stumble are not 

 exactly the same, the reviewer himself being evidently at fault 

 when he conceives that the number of cubic inches of olefiant 

 gas (640) and of oil gas (SOO) found equal to the light of one 

 wax candle per hour, should eack be multiplied by the same 

 multiplier (14*U625) to increase the light ten-fold ; because that 

 in the instance of the olefiant gas it so required it. I feel very lit- 

 tle doubt that the increase of the multipHer will be found to be in 

 the inverse ratio of tlie decrease of carbon, which these gases may 

 contain, still dependent upon the discovery of Count Rumford, 

 " that the quantity of light emitted by a given portion of inflam- 

 mable matter in combustion, is proportional in some high ratio 

 to the elevation of temperature." 



Now how will this agree with Mr. Brande's ratio for coal gas? 

 It seems he forgot to ascertain how much coal gas was equal to 

 the light of one wax candle, but sets about ascertaining the quan- 

 tity of light given off by the largest si:^ed Argand burner when 

 consuming onlv G560 cubic inches (about 3| cubic feet) per hour, 

 which he found equal to only five wax candles. Therefore to 

 obtain by calculation how much coal gas would be equal to ten 

 wax candles, he sets down 6560 -e- 5 = 1312 = the light of one 

 candle, which multiplied by 10= 13120= 10 candles! quite 

 forgetting the Count's theory and his own practice with respect 

 to the cases of the olefiant- and oil gases. Now the fact is, that 

 a large Argand when consuming only 3| feet per hour, instead 

 of 5 feet, is not giving off any thing near so much light as the 

 same quantity would if burnt in a smaller and more propor- 

 tionate sized one *. 



From such a datum so multiplied it is not in the least strange 

 that coal gas of the sp. grav. '443 should cut so poor a figure by 



* The reason of this is best proved by experiment, to he, that the supply 

 of atmospheric air caused by the draught of the glass chimney, is highly 

 disproportioned to the quantity of gas in such case consumed, thereby ex- 

 erting a very coo'ing influence on the t^ame. Had Mr. B. been aware of 

 this fact, he douotless would have adopted some means for its remedy : 

 such as narrowing the draught by applying a taper chimney, or by placing 

 over it a piece of Coarse wire-gauze, or a disc of tin with a smaller opening 

 in its centre tlian that of the glass chimney, either c.f which, so regulated 

 as just to allow the flame not to smoke, would have materially increased 

 the light of his 6560 cubic inch<>s of gas. Surely Mr. Brando does not mean 

 to say that in his experiment the flame was so regulated as to be just be- 

 low smoking r for with coal gas, rich in carbon, I find that the same burner 

 as his, under the same pressure of half inch, will not smoke when consuming 

 five feet per hour and giving a light e |ual to eight or nine wax candles. 

 Mr. R.'s 6560 inches would have given more light if burnt through either 

 a bat's wing burner or a large Argand without a glass. 



the 



