436 
PROCEEDINGS OF THE BRITISH ASSOCIATION. 
second had 4 per cent, more oxygen than the atmosphere, and the third 1 per 
cent. more. This was the result of examination during the day, but at night the 
excess of oxygen had disappeared. On the eleventh day the first jar contained 
2 per cent., the second and third 1 per cent, excess of oxygen. At night there 
was less oxygen than in the atmosphere. On the 20th of June the following 
results were obtained : in first jar 2^ per cent., in second jar per cent., and in 
third jar 4 per cent, less oxygen than in atmospheric air. Some experiments were 
then made to determine the rate of access of air to the plants through the blad¬ 
der, and it was found that when the jars were filled with oxygen, the average 
rate at which it escaped till the internal air was like that of the atmosphere, was 
11 per cent, daily. 
Professor Lindley then read a paper by Mr. Ward on the same subject. The 
Professor observed that Mr. Ward, of Wellclose Square, London, had made 
many experiments on the subject of keeping plants in unventilated vessels, and 
was the original proposer of the plan for preserving plants in this manner. The 
discovery of their being able to be thus preserved, was of great practical import¬ 
ance, as it enabled us to bring plants from foreign climates that could in no other 
way be introduced into this country. The paper commenced, ‘‘ Consider the 
Lilies how they grow.” The attention of the author was first directed to this 
point by accident. He had placed under an inverted jar a chrysalis, and on 
looking at it some time after, he found a Fern and a blade or two of grass had 
grown under the jar, the sides of which appeared to be covered with moisture. 
Taking the hint, he introduced some plants of Uymenophyllum under a jar, 
which grew and flourished in this situation. The Messrs. Loddige then enabled 
him to perform some experiments on a larger scale. The plants were inclosed in 
glass cases, or small green-houses, made tight with paint and putty, but, of 
course, not hermetically sealed, and were watered once in five or six weeks. 
From his experiments the author came to the following conclusions:—First, 
that confining the air secured a more equal temperature for plants, as its expan¬ 
sion and contraction by change of external temperature, by its relation to heat in 
those states, prevented any great or sudden change. This was remarkably 
exemplified in some plants that were brought from India, which v^ere in the 
course of three months successively exposed to 20°, 120°, and 40° of Fahren¬ 
heit. The enclosed plants were very frequently found surrounded by a temper¬ 
ature higher than the external atmosphere. Secondly, that Vascular plants 
required to be grown in a greater quantity of air than Cellular. Thirdly, that 
light must be freely admitted. Fourthly, that the enclosed air must be kept 
humid. This can be done by occasional watering, provided any means of escape 
for the water are allowed, but is not necessary where the water has no means of 
escape. Besides the advantage of enabling us to bring plants from abroad, it 
