THE STOVE. 



11 



(where marine aquatics were cultivated,) nothing could be 

 easier than by the sort of wheel used in the patent mangle to 

 produce it to any extent ; or, by another still more simple 

 plan, known to every engineer, it might be changed seldomer, 

 say only once or twice in twenty-four hours. If a rapid and 

 tortuous motion were required, then let the bottom on which 

 the plants are placed be furnished with small circular wheels 

 placed on its margin, working on pivots, and furnished on their 

 edges with teeth like a spur-wheel. Then let there be a cor- 

 responding row of teeth fixed to the inside of the wall, or 

 side of the cistern, into which they are to work like a wheel 

 and pinion. 



" By this means, pots of plants, set on the small wheels, will 

 have a compound motion ; one round the centre of the small 

 wheels, and another round that of the large bottom. It may 

 be thought by some, that the machinery would be intricate 

 and ti'oublesome, but the power requisite is so very small, that 

 it might easily be obtained by machinery on the principle of 

 the wind-up jack, such as was used by Deacon in his venti- 

 lating i^lolians. This kind of machinery very seldom goes 

 out of order, or requires repair, and no other attention would 

 be necessary than being wound up twice in twenty-four hours, 

 and oiled occasionally. The same vault that contained it 

 might serve for the furnace or boiler," if heated by steam. 



PROPAGATION OF TROPICAL PLANTS. 



Propagation is the first principle which should be acted 

 upon in the formation of a collection of plants, and a strict 

 attention to it annually is no less important after the collection 

 is established, for the lives of plants are as uncertain as those 

 of animals ; and unless attention be paid to keeping up the 

 stock by repeated propagation, many of the short-lived species 

 will soon be lost. To keep up a collection in the first degree 

 of excellence, it is necessary that a certain number of each 

 species be annually propagated, as many of them become un- 

 sightly when old, and by increasing in size preclude the pos- 

 sibility of keeping so many individually. Some tropical 

 plants, however, do not flower until they attain a considerable 



