96 LADIES' FLOWEK GARDENEK. 



is the oxygen, the nitrogen being little else than a diluent tc 

 modify the strength of the oxygen. It was long believed by men 

 of science that plants possessed the power of exuding oxygen, 

 and so formed a prime agent for restoring vitiated air to purity. 

 Later investigations,, however, chiefly by French chemists, have 

 made it evident that plants have no such power, unless when 

 placed under the influence of the sun's rays, or, in other words, 

 that solar light is the grand cleanser of the atmosphere, and with- 

 out which both plants and animals languish and die. With 

 respect to plants in particular, it is ascertained that, while inhaling 

 oxygen and expiring carbonic acid, their leaves possess the 

 remarkable property, in conjunction with the sun's light, of 

 re-transforming the carbonic acid into oxygen. At night, when 

 the light of day has departed, the expired carbonic acid may be 

 detected in the neighborhood of plants ; and hence one cause of 

 injury to health by breathing night air ; but when the morning 

 sun again bursts upon the scene, a great chemical process com- 

 mences in the atmosphere the carbonic acid is decomposed, 

 oxygen is evolved, and all nature rejoices in a recreation of its 

 appropriate nourishment. 



A question will here readily occur what species of plants are 

 best adapted for these domestic greenhouses ? We are fortu- 

 nately enabled to answer this inquiry by referring to a learned 

 paper on the subject by Mr. Ellis, which was read to the Botani- 

 cal Society of Edinburgh, January 13, 1839, and afterwards 

 published in the Gardener's Magazine, and also as a separate 

 pamphlet. According to this gentleman's statement, the plants 

 most suitable are " those which partake largely of a cellular 

 structure, and possess a succulent character, and especially those 

 which have fleshy leaves ; whilst, on the contrary, the continued 

 humidity is unfavorable to the development of flowers of most 

 erogenous plants, except such as naturally grow in moist and 

 shady situations." Plants, therefore, which have to grow and 



