Messrs. Gladstone on the Ch^owth of Plants in various Gases, 217 



oxygen gases, the vegetable being supplied, as in nature, with 

 the carbonic acid necessary for its growth through the agency 

 of animal life. A large glass receiver capable of containing 177 

 cubic inches was filled with oxygen and hydrogen in the propor- 

 tion of two measures of the latter to one of the former gas, in 

 fact, in exactly the proportions requisite to form water. Into 

 this atmosphere was introduced a pansy in flower, together with 

 a few common house-flies and some sugar, and it was kept from 

 communicating with the external atmosphere by being placed 

 over water. A precisely similar arrangement was made in an^ 

 other receiver of similar capacity, but with the normal atmo- 

 sphere in place of the mixed gases. It was anticipated that the 

 plant would derive its nutriment from the aqueous vapour, and 

 the carbonic acid produced by the respiration of the flies, while 

 these again would feed upon the sugar ; and we should thus have 

 the same balance between the vegetable and animal kingdoms as 

 obtains in nature, except that the animal would not feed upon 

 the very plant which its breath nourished, a circumstance which 

 it was obviously necessary for us to avoid. Besides ascertaining 

 whether the pansy would flourish in mixed hydrogen and oxygen 

 gases — the direct object of this experiment — it would afford an 

 opportunity of observing any effects which the unnatural atmo- 

 sphere might have upon the insects themselves. The pansy con- 

 tinued in a healthy condition for some time. As to the flies, it 

 did not appear that the substitution of hydrogen for nitrogen in 

 the atmosphere had any marked immediate effect upon their 

 breathing ; and thus the observations of M. Regnault upon ether 

 living creatures were confirmed by an instance drawn from the 

 Articulata. But it was curious to observe the effects that resulted 

 from the low specific gravity of the gaseous mixture. The larger 

 flies when first introduced found themselves unable to walk up 

 the glass, nor when they shook their wings did it assist them in 

 mounting into the air; if they launched themselves from any 

 prominent object, it was only by a great effort that they were 

 able to fly an inch or two before falling to the bottom. While 

 the comparative experiment made with atmospheric air presented 

 a scene of animation by the rapid evolutions of the winged in- 

 sects, and their buzzing against the glass which confined them, 

 the flies walked slowly and in perfect silence about the interior 

 of the vessel containing mixed hydrogen and oxygen. 



Experiments were made in nitrogen gas. A pansy in flower, 

 a young stock, and a grass-plant (Poa annua) in flower, were 

 placed in atmospheres of this gas with the same arrangements as 

 in the preceding instances. Another young stock was placed in 

 air under similar circumstances for the sake of comparison : it 

 was thought unnecessary to repeat the comparative experiment 



