BOOK II. 



ORNAMENTAL HOT-HOUSES, 



817 



a supporting column 

 at each angle, raised 

 to the height of a 

 hundred or a hun- 

 dred and fifty feet 

 from the ground, to 

 admit of the tallest 

 oriental trees, and the 

 undisturbed flight of 

 appropriate birds a- 

 mong their branches. 

 A variety of oriental 

 birds, and monkeys, 

 and other animals, 

 might be introduc- 

 ed ; and in ponds, a 



stream made to run by machinery , and also in salt lakes, fishes, polypi, corals, and other pro- 

 ductions of fresh or sea water might be cultivated or kept. The great majority of readers 

 will no doubt consider these ideas as sufficiently extravagant ; but there is no limit to human 

 improvement, and few things afford a greater proof of it than the comforts and luxuries man 

 receives from the use of glass a material, as Cuvier observes (Magazin Encylo}>dique, 

 1816), manufactured from seemingly the most useless debris of our globe, and an insig- 

 nificant plant (salicornea) found on sea-shores. In northern countries civilised man could 

 not exist without glass : and if coal is not discovered in these countries, say in Russia, 

 it may at some future period become a question whether, instead of separate fires and 

 stoves, double windows, &c. the most economical mode of procuring a proper temper- 

 ature will not be by at once to cover whole towns with immense teguments of glass, and 

 heating by steam or otherwise, the enclosed air common to all the inhabitants ; or where 

 glass was considered too expensive, whole villages might be covered with a roof of boards, 

 and lighted night and day in the winter season by gas previously obtained from the fuel 

 used to produce the steam : or the gas might be employed for heating, either by the 

 generation of steam, or passing the air heated by the flame through metallic tubes. 



6180. Tftf aquarium. The greater number of exotic aquatics being stove plants, a cistern of water for 

 their culture is commonly placed in the bark-stove, generally at one end of the pit, and so as to be as 

 near thie light as possible. The E)uke of Marlborough, however, and some others, have erected houses 

 on purpose for this beautiful class of plants, substituting a 

 large cistern for the bark-pit. The aquarium, at White 

 Knights, (fig. 578.) built by Todd, " is constructed with a 

 span roof of glass ; the sides and ends are also of glass, as 

 low down as the top of the flue. A cistern occupies the 

 interior of the house, having a walk round it ; it is lined 

 with lead, and filled with a mixture of mud and water, 

 proper for the reception and growth of such plants as require 

 aqueous nourishment. A flue goes round, directly under 

 the bottom of the cistern, for the purpose of keeping the 

 water of a certain temperature. Another flue goe round 

 the house above ground, and terminates in a chimney at 

 the north-west corner. The bottom of the cistern, to re- ' 

 ceive the lead, is formed with slates, supported by transverse bars of cast-iron ; a bottom of wood would 

 have been more convenient for laying the lead upon, but as the ftues are so near the bottom of the cistern, 

 danger of fire was apprehended. The cistern is supplied with water by means of a pump placed at a con- 

 venient distance for that purpose." (Plans for Green-Houses, &c. p. 17.) This aquarium suits very well 

 for such aquatics as grow to some height above the water ; but for those whose leaves float on its surface, 

 as is the case with the most numerous and beautiful genus of this class (Nymph&a), it is too far from the 

 light. A more perfect plan would be, to have the cistern close under the front glass, and to have that 

 glass rather flat, say at an angle of 15 ; or two cisterns might be formed, one in the back part of the 



579 



