THE GARDENER. 



13 



in its texture, too mucli approaching the nature of 

 peat. In short, he must study the nature of earths 

 and fertiUzing substances, because on their proper 

 combinations the success of plants depends. 



I obtained from a chemist the analysis of a pecu- 

 liarly fertile sand in my present neighbourhood, which, 

 "when mixed in moderate quantities with the scourings 

 of ditches and fresh turf, forms, with animal manure, 

 an admirable compost for most common vegetables. 

 The following are the substances : — Chlorine, sulphu- 

 ric, carbonic, and phosphoric acid, sodium, soda (oxide 

 of sodium), potassium, potass (oxide of potassium), 

 magnesium, magnesia (oxide of magnesium), lime, 

 iron, oxide of iron, peroxide of manganese, lead, sul- 

 phur, silex, alumina, oxide of manganese. 



I merely mention this as illustrative of the fact, that 

 various elementary substances enter into the composi- 

 tion of soil. There is also a most important se- 

 condary substance called Humus, the most fertile of 

 all matter, created by the decomposition of animal and 

 vegetable substances. Soil which has seven per cent, 

 of this matter is considered very rich, and if even 

 less than half that quantity be present in a good loam, 

 the gardener may be very well satisfied for ordinary 

 purposes. Humus, though consumed by plants in 

 the progress of growth, becomes, by the beneficent 

 provisions of the Creator, continually reproduced by 

 the decay of the matter which yields it. It may easily 

 be known by its appearance v;hen separated from all 

 other earthy matter : it is dark-coloured, brittle, and 

 carbonaceous, and will not dissolve in water until 

 exposed for some time to the action of the atmosphere. 

 The value of this dark-coloured, yet light and elastic 

 substance arises from its porousness, and the great 

 quantity of carbonic acid which it contains ; and whilst 

 it acts as a manure to the soil, it renders it more per- 

 vious to moisture, more accessible to atmospheric 



