GROWTH OF PLANTS IN CLOSED GLASS CHAMBERS. 201 



bonic acid (which finds its way through the crevices beneath the 

 glass cover), without being also exposed to the impurities which 

 the atmosphere contains. In London and other large towns, the 

 air is loaded with particles of soot and dust, which are so inju- 

 rious to vegetation, that none but the most hardy plants will 

 flourish there without some protection ; yet under this system, 

 the most delicate and beautiful plants may be reared, provided 

 they are sufficiently supplied with light and warmth. Again, 

 many plants are killed by exposure to the sea-air during long 

 voyages ; this being loaded with particles of salt. But under 

 this protection, plants have been successfully transported to Eng- 

 land from the most distant quarters of the globe, which could 

 only be previously introduced by seeds. By the adoption of this 

 plan, many who take an interest in the cultivation of plants too 

 delicate for our own climate, may indulge their taste at a small 

 expense. A window should be selected with a southern aspect, 

 or nearly so, and a second pair of sashes should be fixed at the 

 distance of a foot or 18 inches within or outside the first, as may 

 be most convenient, the fitting of the whole being as tight as 

 possible, consistently with the easy movement of the inner sashes. 

 In the space at the bottom, a trough is placed containing moist- 

 ened earth ; and the plants grown in it should be so trained, as 

 to expose the surface of their leaves to the light as freely as 

 possible. If a winter warmth is required, the window of a 

 sitting-room in which a fire is constantly maintained, should be 

 selected ; and this will suffice to grow many plants which natu- 

 rally inhabit the warmer regions of the globe. This method 

 is particularly adapted for the growth of Ferns. The public 

 are indebted for this important system, to Mr. N. B. Ward, of 

 London. 



