and of Rural Improvement generally ', during J 842. 647 



Lymburn, who is at once an excellent chemist and physiologist, 

 and a cultivator of great experience, and of extensive observa- 

 tion, both in gardens and farms. 



The doctrines of Liebig have been criticised by Dr. Schleiden 

 and some writers, and defended by Drs. Gregory and Daubeny 

 and others; for these discussions we refer to the Gardener's 

 Chronicle for 1842, p. 403. 435. 469. and 493. Liebig's lead- 

 ing principle, that the carbon of plants is chiefly derived from 

 the atmosphere, appears to us to remain a truth ; and one more 

 remarkable has seldom been promulgated. Its great practical 

 use is, that it suggests the immense importance of admitting 

 air to the roots of plants, either by using rough, stony, turfy 

 soil, as is now being done in the case of plants grown in 

 pots, or in limited masses of soil ; and, under ordinary circum- 

 stances of culture, of stirring the soil to facilitate the descent 

 of air to the roots ; or, in the case of fruit trees, of inviting 

 the roots to the surface, by the shade and moisture produced 

 by mulching. 



As a general result of all that has been written or experi- 

 mented on during the past year, we may state that the great 

 value of animal manures is confirmed, and that the higher the 

 animal is in the scale of organisation, and the better he is fed, 

 the more valuable will be the manure. The preeminent value 

 of night soil, and all the liquid matters produced in dwelling- 

 houses, cattle sheds, and farm-yards, containing ammonia or 

 any of the ammoniacal salts, though long known and duly ap- 

 preciated on the Continent, has been brought prominently for- 

 ward to the notice of British cultivators, both by reasonings and 

 experiments. " The powerful effects of urine as a manure," 

 Liebig observes, " are well known in Flanders, but they are 

 considered invaluable by the Chinese, who are the oldest agri- 

 cultural people we know. Indeed, so much value is attached to 

 the influence of human excrements by these people, that the 

 laws of the state forbid that any of them should be thrown 

 away, and reservoirs are placed adjoining every house, in which 

 they are collected with the greatest care." {Chemistry and its 

 Application to Agriculture, 8fc, 2d ed. p. 183.) The great value 

 of wood ashes, and of the ashes of burnt vegetables generally, 

 and especially those produced by a smothered combustion, has 

 been long known, but comparatively forgotten, till the recent 

 stimulus given by Liebig has brought them again conspicuously 

 into notice. We may add that their value has been confirmed 

 by Mr. Barnes (p. 558.), by what, to him, was as completely 

 a discovery, as if wood ashes or charcoal ashes had never been 

 used before. 



Experimental Culture. — In horticultural practice perhaps the 

 most important feature that has lately been introduced is, the 



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