648 Summary View of the Progress of Gardening, 



use of rough turfy soil, mixed with fragments of freestone and 

 pebbles, in pot culture. The great advantages of this mixture 

 are, a more perfect drainage, a more ready reception of water, 

 a more free transmission of it through the whole mass, and, in 

 consequence of the absorption of this element by the stones and 

 pebbles, a supply of it from them to the roots, even when the soil 

 is quite dry. Plants growing in soil thus composed can hardly 

 ever suffer from being over-watered, or from the temporary 

 neglect of watering ; and, if this practice could be adopted in the 

 open garden on a large scale, it would be found as beneficial for 

 culinary crops and fruit trees in beds and borders, as it is for 

 ornamental plants, pine-apples, or orange trees, in pots. For 

 orange trees in tubs and boxes this mode of using strong rough 

 soil will be found of immense advantage ; and it will be no less 

 so in beds and borders in conservatories, which, when composed 

 of sifted soil, very often get compact and sodden. That excel- 

 lent cultivator, Mr. Barnes, in addition to small stones uses 

 charcoal, sometimes in small pieces, and sometimes in powdery 

 refuse (see p. 558.). In looking into various works to ascertain 

 how far charcoal had been before used in cultivation, we find in 

 the Nouveau Cours complet d Agriculture, ed. 1819, vol. iv. p. 71., 

 that the places in the forests where heaps of charcoal had been 

 burnt, and where a great quantity of charcoal dust is usually 

 found, are sterile for a greater or less number of years. In 

 sandy soils these spots will often bear crops the second year, 

 while on clayey soils they have been known not to bear a crop 

 for eight or ten years. These sterile places, however, when 

 they are restored to fertility, bear immense crops ; and the char- 

 coal-makers, being aware of this circumstance, sow or plant on 

 them tobacco, woad, and other plants which exhaust the soil. 

 An English gentleman, who has been a good deal in the interior 

 of France, informs us that it is customary about Lyons for the 

 peasants to petition the proprietors of forests for permission to 

 sow mustard seed (well known to be a very exhausting crop) in 

 the places where charcoal has been burnt. The cause of the 

 sterility of the charcoal spots is, doubtless, the excess of potash, 

 which, in the case of sandy soil, is sooner washed in by the rains. 

 The writer referred to, in endeavouring to account for the power- 

 ful effects of charcoal as a manure, first notices that the pro- 

 perty of charcoal to absorb and retain moisture powerfully, and 

 give it out again slowly and during a long time, was well 

 known, and that this rendered it a valuable addition to light 

 soils apt to suffer from great drought. A very good memoir on 

 the use of charcoal, he informs us, has been written by M. Ta- 

 tin, the essence of which is said to be embodied in his Principes 

 raisonnes et pratiques de la Culture. Though charcoal is con- 

 sidered almost indestructible, yet it is found liable to decompo- 



