I860.] Agriculture. 433. 



bushels per acre ; and in the form of ammonia, 50-4 bushels per acre. 

 Where nothing had been used as manure, the produce was 40-9 bushels 

 per acre ; and where guano ash alone was used, the produce was 40" 1 

 bushels per acre. As Dr. Anderson states, although these experi- 

 ments will be the better for confirmation, yet in the meantime they 

 establish beyond all doubt that uric acid is capable of promoting the 

 growth of plants and that, as a source of nitrogen, it is on the whole 

 equal to sulphate of ammonia or guano. 



Mr. Lawes has subjected to an experimental test the suggestion of 

 Professor Voelcker, that in order to increase the efficiency of Peruvian 

 guano as a manure for root crop, it would be well to moisten it with 

 sulphuric acid, this being best effected by mixing it with sawdust, 

 over which the sulphuric acid had been poured. It was supposed 

 that the guano would be increased in efficiency, both by its volatile 

 ammonia being thus fixed, and by its phosphate of lime being rendered 

 soluble. The experiment performed in a dry season, which produced 

 a very poor crop of roots, did not corroborate the suggestion : the 

 crop from 8 tons of dung and 200 lbs. of Peruvian guano in its natural 

 state being rather better than where the guano added to the dung had 

 been previously treated as was suggested. On the other hand, when 

 to both of these dressings 2 cwt. of superphosphate of lime had been 

 added, there was a corresponding small advantage the other way. 

 The results on the whole, therefore, are nugatory ; and as the cost of 

 the acid and expense of mixing were thus spent for nothing, the experi- 

 ment, so far as it goes, discourages the practice which had been recom- 

 mended. Several sets of experiments have been lately published on the 

 value of ground coprolites, as a manure for the turnip crop. Mr. Bald- 

 win, of Glasnevin, Dublin, Mr. Kensington, F.C.S., and others, have 

 observed a marked increase of produce from their use, which contradicts 

 the general impression of their worthlessness in an undissolved state. 

 The experiments need, however, repetition. 



Dr. Voelcker has called the attention of the English Agricultural 

 Society to a source of potash as a manure which has recently become 

 available. A great thickness of potash, bearing earthen beds, is tra- 

 versed in the Strassfurth Salt Mines, before the enormous deposit of 

 pure rock salt is reached which there exists. Various extracted potash 

 salts are obtained from these preliminary beds, some of them deliques- 

 cent muriates, and one, a sulphate, selling at about SI. a ton, and con- 

 taining 20 per cent., which is likely to be imported into this country for 

 agricultural pxirposes. Dr. Voelcker recommends experiments with 

 these crude potash salts upon light soils for turnips, potatoes, and 

 clover : (1) alone, at the rate of 3 cwt. per acre ; (2) alone, in com- 

 parison with an equal quantity of common salt ; (3) mixed with 

 an equal quantity of superphosphate of lime ; and (4) mixed with 

 3 cwt. each of both common salt and superphosphate. The bean 

 crop has been benefited in farm practice by the application of wood 

 ashes as a manure, and these potash salts may thus also be applied 

 to beans with some prospect of success. 



Baron Liebig has published a letter upon the progress of the 

 artificial manure manufacture in the Grand Duchy of Hesse, de- 

 void ii. 2 H 



