604' Liehig^s Organic Chemistry. 



representations of the flowers, which will be coloured faithfully after nature ; 

 and the printing department will also be executed with greater care than of 

 late." 



The paper and print in this October number are certainly better than they 

 have hitherto been, and the figure of Ipomoe^a Lef\n'i is good, and certainly 

 of greater artistical merit than any of those in the FlorisCs Journal, though 

 these are an immense deal better than even the figures in Paxton^s Magazine 

 were at the commencement of that work. With respect to the articles in the 

 Floricultiiral Magazine, tliey will be liked better by the practical gardener 

 than those in the F/orisfs Journal, but not so well by the lover of speculative 

 science, and of vigorous, eloquent, and correct language. Both works we hold 

 to be essential, as well to the young gardener as to the amateur. 



Art. IV. Organic Chemistry in its Applicatioji to Agriculture and 

 Physiology. By Justus Liebig, M.D. Ph.D. F.R.S., &c., edited 

 from the manuscript of the author by Lyon Playfair, Ph.D. 8vo, 

 pp. 387. London, IS-tO. 



Though we have received this work too late in the month, yet we con- 

 sider it of so much importance as to deserve an interim notice. 



Part I. treats of the chemical processes in the nutrition of vegetables, p. 1. 

 to 21 1., from which we give the following extract : — 



" The Art of Culture. — The conditions necessary for the life of all vege- 

 tables have been considered in the preceding part of the work. Carbonic acid, 

 ammonia, and water yield elements for all the organs of plants. Certain 

 inorganic substances, salts, and metallic oxides, serve peculiar functions in 

 their organism, and many of them must be viewed as essential constituents of 

 particular parts. 



" The atmosphere and the soil offer the same kind of nourishment to the 

 leaves and roots. The former contains a comparatively inexhaustible supply 

 of carbonic acid and ammonia ; the latter, by means of its humus, generates 

 constantly fresh carbonic acid, whilst, during the winter, rain and snow intro- 

 duce into the soil a quantity of ammonia, sufficient for the developement of 

 the leaves and blossoms. 



" The complete, or, it may be said, the absolute, insolubility in cold water 

 of vegetable matter in progress of decay (humus), appears, on closer con- 

 sideration, to be a most wise arrangement of nature. For, if humus possessed 

 even a smaller degree of solubility than that ascribed to the substance called 

 humic acid, it must be dissolved by rain water. Thus, the yearly irrigation 

 of meadows, which lasts for several weeks, would remove a great part of it 

 from the groimd, and a heavy and continued rain would impoverish the soil. 

 But it is soluble only when combined with oxygen ; it can be taken up by 

 water, therefore, only as carbonic acid. 



" When kept in a dry place, humus may be preserved for centuries, but 

 when moistened with water, it converts the surrounding oxygen into carbonic 

 acid. As soon as the action of the air ceases, that is, as soon as it is de- 

 prived of oxygen, the humus suffers no further change. Its decay proceeds 

 only when plants grow in the soil containing it ; for they absorb by their 

 roots the carbonic acid as it is formed. The soil receives again from living 

 plants the carbonaceous matter it thus loses, so that the proportion of humus 

 in it does not decrease." (p. 117.) 



Part II, p. 217., to the end of the volume, treats of the chemical pro- 

 cesses of fermentation, decay, and putrefaction. 



Our readers will thus be enabled to form an idea of the contents of the 

 work, and of the manner in which the author treats his subjects, and, we 

 think, they will agree with us, that it promises to be one of the most instruc- 

 tive books for the scientific cultivator and the agriculturist, that has appeared 

 since the time of Sir Humphry Davy's Agricultural Chemistry. 



