oO ON THEORY AND PRACTICE. 



at least. These pans should have a layer of broken brick and some 

 clay about 4 inches thick at the bottom, and be filled with stiff pond 

 mud, or strong yellow loam, fit for growing melons, and the surface 

 of the mud should be covered with stone and broken brick. The pans 

 should be sunk, not less than one foot nor more than three, below the 

 surface. Some species must not be more than six inches under, but 

 most of the strong growing ones, from two to three feet. I should 

 leave them always under water unless experience shewed, that any 

 species perished in winter, which I do not think probable, unless it 

 were Nelumbium speciosum, but I suspect this, which is difficult to 

 keep elsewhere, would survive in such a situation. 



The waste water should run off by a siphon from the bottom of the 

 tank, so as always to draw off the coldest water, and if the heat was 

 found too great for the plants in winter, when they die down, the waste 

 might then be allowed to flow off at the top, so that the bottom water 

 in which the plants were sunk might be coldest. 



The species I should recommend for the experiment are Nymphoea 

 Lotus, N. rubra, N. ccerulea, Nelumbium speciosum, Euryale ferox, 

 Pontederia crassipes, and Limnocharis Ilumboldtii, but particularly 

 the five first, which are strong growing plants. Nymphoea Lotus grew 

 almost like a weed with me last year. The best season to put them in 

 would be March, as the offsets abound most at that time, and some 

 would flower in May. Some gold and silver fish, in the same place 

 would be highly ornamental, and consume the filth of the engine. 



Of course the plants will not succeed if the boiler of the steam 

 engine is of copper, or if the temperature of the tank ever much ex- 

 ceeds 90°, but by proportioning its surface to the supply, this might 

 easily be managed. If the glass case be high enough probably many 

 Orchidea would succeed suspended over the water in the same place. 

 One might be constructed to cover a small reservoir. I hope the 

 above will meet the eye of some one able to make the experiment, 

 and who will communicate his success. 



ARTICLE II.— REMARKS ON THEORY AND PRACTISE, 



With some Observations on the Food of Plants, Sfc. 



BY JOSETH HAYWARD, ESQ., LIME REGIS, DORSETSHIRE. 



Your Floricultural Cabinet I think well calculated to make a valuable 

 work if you adhere to the proper principle, and it appears to me you have 

 it in view, which is, to diffuse a knowledge of the cultivation of Plants 

 deduced from practice. The object of every cultivator is to produce 

 certain effects ; and when people undertake to produce any effect, 

 who do not know the cause, they generally form some supposition of 

 what the cause is ; such supposition forms Theory, which may be true 

 or false, and as the latter is too often the case, the students of every 

 art, are apt to treat Theory with contempt, and to depend upon the 



