OF THE MOISTURE OP THE SOIL. 117 



nave no parallel. In this country the melon does not 

 succeed if the roots are immersed in water, as I ascer- 

 tained some years ago, in the garden of the Horticul- 

 tural Society, by repeated experiments. Melons 

 were planted in earth placed on a tank of water, into 

 which their roots quickly made their way; they 

 grew in a curvilinear iron hot-house, and were trained 

 near to the glass, and consequently were exposed to 

 all the light and heat that can be obtained in this 

 country. They grew vigorously and produced their 

 fruit, but it was not of such good quality as it would 

 have been had the supply of water to the roots been 

 less copious. Thus, in the tropics, the quantity of rain 

 that falls in a short time is enormous ; and plants are 

 forced by it into a rapid and powerful vegetation, 

 which is acted upon by a light and temperature 

 bright and high in proportion, the result of which is 

 the most perfect organization of which the plants are 

 susceptible : but, if the same quantity of water were 

 given to the same plants at similar periods in this 

 country, a disorganisation of their tissue would be 

 the result, in consequence of the absence of solar 

 light in sufficient quantity. 



The effect of continuing to make plants grow in 

 a soil more wet than suits them is well known to be 

 not only a production of leaves and ill-formed shoots, 

 instead of flowers and fruit, but, if the water is in 

 great excess,. of a general yellowness of appearance, 

 owing, as some chemists think, to the destruction, by 

 the water, of a blue matter which, by its mixture 

 with yellow, forms the ordinary verdure of vegeta- 



