230 Mr. Faraday on the Liquefaction of Gases. 



experimenter, I was surprised to find several recorded cases. 

 I have thought it right therefore to bring these cases together, and 

 only justice to endeavour to secure for them a more general at- 

 tention, than they appear as yet to have gained. I shall notice 

 in chronological order, the fruitless, as well as the successful, at- 

 tempts, and those which probably occurred without being ob- 

 served, as well as those which were remarked and described 

 as such. 



Carbonic Acid, &c. — The Philosophical Transactions for 1797, con- 

 tain, p. 222, an account of experiments made by Count Rumford, to 

 determine the force of fired gunpowder. Dissatisfied both with the 

 deductions drawn, and the means used previously, that philosopher 

 proceeded to fire gunpowder in cylinders of a known diameter and 

 capacity, and closed by a valve loaded with a weight that could 

 be varied at pleasure. By making the vessel strong enough and 

 the weight sufficiently heavy, he succeeded in confining the pro- 

 ducts within the space previously occupied by the powder. The 

 Count's object induced him to vary the quantity of gunpowder in 

 different experiments, and to estimate the force exerted only at 

 the moment of ignition, when it was at its maximum. This force 

 which he found to be prodigious, he attributes to aqueous vapour 

 intensely heated, and makes no reference to the force of the gase- 

 ous bodies evolved. Without considering the phenomena which 

 it is the Count's object to investigate, it may be remarked, that 

 in many of the experiments made by him, some of the gases, and 

 especially carbonic acid gas, were probably reduced to the liquid 

 state. The Count says, 



" When the force of the generated elastic vapour was sufficient 

 to raise the weight, the explosion was attended by a very sharp 

 and surprisingly loud report ; but when the weight was not raised, 

 as also when it was only a little moved, but not sufficiently to 

 permit the leather stopper to be driven quite out of the bore, and 

 the elastic fluid to make its escape, the report was scarcely audi- 

 ble at the distance of a few paces, and did not at all resemble the 

 report which commonly attends the explosion of gunpowder. It 

 was more like the noise which attends the breaking of a small 





