218 Messrs. Gladstone on the Growth of Plants in various Gases, 



with the others. The pansy and the stock dried up and died in 

 the course of a day or two ; but the grass-plant grew and seemed 

 healthy for several weeks, mouldiness only appearing on partially 

 decayed portions. We surmised that the deleterious effects of 

 this gas, which we as well as other experimenters had observed, 

 might be attributed to the phosphorus vapour which it always 

 contains when prepared by the usual method. Accordingly, we 

 have subsequently employed pure nitrogen gas evolved by the 

 mutual action of nitrite of potash and chloride of ammonium at 

 a high temperature. A pansy placed in this atmosphere under 

 a glass vessel of 54 inches capacity inverted over water, remained 

 flowering and vigorous for between two and three weeks. 



It is curious to remark the readiness with which mouldiness 

 grows in nitrogen gas. A receiver half-full of nitrogen happened 

 to be left standing over the pneumatic trough, and a bung was 

 floating 6n the surface of the water inside. In a few days' time 

 a white growth was observed upon the bung ; and not on it only, 

 but also in patches over the surface of the water. A bottle also 

 partially filled with the gas was standing inverted in ordinary 

 spring- water ; the surface of the liquid inside was soon found 

 covered with small patches of mould, which continued to increase. 



A pansy and grass plant were placed in a receiver containing 

 180 cubic inches of pure oxygen gas, inverted as usual over 

 water. Both plants were in flower at the time of their intro- 

 duction; they grew considerably taller, and the Poa showed 

 extraordinary luxuriance in fructification. After about twenty- 

 four days the grass became mouldy, and the pansy drooped a 

 short time afterwards. 



Two similar plants were placed under a receiver of similar 

 capacity, but filled with nitrous oxide. In order to exclude the 

 external air, the glass vessel was inverted over water saturated at 

 the ordinary temperature with the same gas. The water how- 

 ever gradually absorbed the nitrous oxide within, allowing it to 

 diffiise into the atmosphere without ; thus the liquid rose in the 

 receiver, but it allowed of the continuation of the experiment for 

 two months, during which time no extraordinary effect upon 

 either plant was observable. Davy records a trifling experiment 

 upon a sprig of mint, which, so far as it went, indicated the 

 innocuous character of his laughing gas ; and Drs. Turner and 

 Christison * found that 72 cubic inches of this, mixed with air 

 in a vessel of 509 inches capacity, produced no visible effect upon 

 a mignonette plant in forty-eight hours. They do not appear to 

 have pursued the investigation further. 



The same experimenters concluded that carbonic oxide is pro- 

 bably of the same class of gaseous poisons, in respect to plants, 

 * Brewster's Journal, Januans 1828. 



