Agricultural Implements and Produce. 57 



Mr. Way attriliutes the power possessed by soils to remove 

 various alkaline bodies (as potash, ammonia, &c.), from solution 

 in water, to the existence of a class of double silicates of alumina 

 and another base, which is generally lime or soda. Mr. Way has 

 succeeded, for the first time, in producing this class of salts ; and 

 he argues, from the effects observed in soils, that these latter 

 contain the silicates in question in small quantity, and hence 

 their power to preserve soluble manures from loss by rain and 

 drainage. His second paper on this subject refers to the action 

 of lime on soils ; and he endeavours to show, from the large 

 quantity of ammonia existing in almost all soils, which, according 

 to his experiments, very far exceeds the doses of this alkala 

 usually applied in manure, that lime acts much in the same waj 

 as ammoniacal manures themselves, by furnishing indirectly st 

 supply of nitrogen to plants. The effects of over-liming are ac- 

 counted for in the same way, 



Mr. Way has also given an account of his examination of cer- 

 tain beds Ivins: immediately below the chalk formation, which 

 contain large quantities of what is known to chemists as " soluhh 

 silica^ This form of silica has not hitherto been met with natu- 

 rally, except in the case of some strata in the Department des- 

 Ardennes, in France, which were examined four or five years 

 ago by M. Sauvage. From their peculiar nature they are sup- 

 posed to be available with advantage for many purposes in the 

 arts, and as a source of soluljle silica for agricultural use. 



The subject in the chemistry of agriculture, which has lately, 

 however, attracted the greatest share of attention, both in this- 

 country and abroad, is that of the source from which plants 

 derive their nitrorjen. It has been satisfactorily proved that 

 plants growing in the ordinary way often contain more of the 

 element nitrogen than they can obtain from the soil in which 

 their roots are placed ; and it is obvious that in some way or 

 other this accumulation is derived from the atmosphere. Now, 

 the air surrounding the globe is composed of a mixture of nitro- 

 gen and oxygen gases in the proportion of about four parts of 

 the former to one part of the latter ; it also contains small quan- 

 tities of otlicr gases, such as carbonic acid, nitric acid, and am- 

 monia. The question at issue is, as to whether plants can, under 

 any circumstances, make use of the great bidk of the nitrogen of 

 the air in building up their tissues, or whether they derive ths 

 observed excess from the ammonia and nitric acid in the air. 

 This question, the interest of which, both in a purely scientific 

 and agricultural point of view, can hardly be overrated, has en- 

 listed the energies of chemists on liotli sides, and has given rise 

 to some admirable researches. It has als(j involved tlie extended 

 examination of air and rain-water, in order to ascertain how 



