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 3i 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 

 1 1 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 Hymenophyllum 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 were 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 



