98. SckeU's \ Land 'scape-Gardening. 



The modes of action of these saline manures are not well understood yet. 

 If we suppose them to act as food, and limit the meaning of this term to its 

 general acceptation of nutritious substances, the carbonates and nitrates, and 

 the salts of ammonia, will be principally valuable. If we extend the meaning 

 of the term food, so as to include everything absorbed as constituents of 

 the plant, the salts of potash and lime, and the phosphates and silicates, 

 will be the next most valuable; the sulphates and muriates, and the 

 salts of soda, are found only in small quantities in cultivated plants. If 

 we allow part of the action to be as condiments, in the way in which 

 common salt is beneficial to animals, and that they act in assisting the che- 

 mical compositions and decompositions going on in the sap of the plant, 

 which has not yet been taken into view, we must trust to observation 

 and experiment for a knowledge of their effects in this way ; what is not ab- 

 sorbed as a constituent will be excreted, and though great effects may be pro- 

 duced from small quantities, the limits of application will be sooner attained. 

 If, again, we take another view of the subject, and consider these substances 

 to act chemically in the soil, the stomach of the plant, dissolving the insoluble 

 organic substances abounding more or less in all soils ; the sulphates and mu- 

 riates, or the acids themselves of these substances, and the salts of soda, 

 potash, and ammonia, especially the first, will have the most powerful effect. 

 The benefits, however, of all these as solvents would cease, as lime does with 

 the applications if long-continued ; and in poor soils, as in the border at 

 Roselle, common farm-yard manure would be predominant. As food, except 

 for the nutritious substances, the quantities needed, especially of some sorts, 

 are so small, that a limit in the benefit of their application may be soon ar- 

 rived at, and in some places sooner than in others. To such as grain crops 

 from peat soils, the phosphates and silicates would be most needed ; and the 

 phosphates from bones, and the chaff of grains, which in some places is sold 

 cheap, would be very beneficial ; the silicates would be got from the straw of 

 former crops on other soils. The small quantities of sulphuric acid, soda, 

 and common salt, needed as constituents, would likely be found naturally, in 

 sufficient quantity, in the soil and the ordinary manures applied. Analyses of 

 different plants, in different soils, and repeated, are much wanted to enable 

 decisions to be arrived at. On such subjects we are likely to obtain much 

 valuable information from Professor Johnston, as the Lectures proceed; from 

 his great chemical knowledge, joined to the accumulation of experiments 

 conducted under his direction, and from the great ardour he displays in the 

 cause, which ought to be fostered and encouraged by every means, as the 

 benefit is a national one in which all are interested. Of guano, the pro- 

 fessor gives two analyses of his own, which reduce the quantities of ammonia 

 very much from all formerly published analysations ; one of them only about 

 8 per cent, instead of 30 and upwards as before. He gives also a table and 

 prices of a method of making artificial guano, at a much cheaper rate than 

 the imported. 



Art. VI. The Landscape-Gardening of F. L. von Sckell of Munich, 

 Translated from the German for the " Gardener's Magazine. 



(Continued from our preceding Volume, p. 605.) 



XI. When Lakes can be introduced in Gardens they add extremely to their 

 Beauty. How to form and stake them out, fyc. 



1. The character of a lake is very different from that of a 

 stream, because the former extends both in length and breadth, 



