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MISCELLANEOUS COMMUNICATIONS AND 

 NOTICES. 



1. — On Experiments ivith Pernvian Guano mixed with a small 

 quantity of Sulphuric Acid. By J. B, Lawes, F.R.S., F.C.S. 



In Vol. XXV., Part 1, of the ' Journal of the Royal Agricultural 

 Society' (1864), Professor Voelcker published a very valuable 

 paper on Peruvian Guano, and concluded with some practical 

 suggestions for increasing its efficacy by rendering soluble a con- 

 siderable portion of the nitrogenous matter and phosphates which, 

 in its natural state, exist in it in an insoluble condition. Every 

 ■farmer of the present day is well acquainted with the importance of 

 Peruvian guano as a manure, and knows what a high price he is 

 required to pay for it ; and as there is but little probability of a 

 reduction in its cost, any suggestions for economising its use are 

 deserving of careful consideration, and of being put to the test of 

 ■careful experiment, more especially so since the present agents 

 ■of the Peruvian Government have removed the restrictions which 

 were formerly imposed upon the dealers in guano, and now permit 

 them to employ it in the manufacture of compound manures. 



Professor Voelcker's suggestion is to render soluble a larger 

 amount of the phosphoric acid and nitrogenous matter of the 

 guano, by mixing with it about 5 per cent, of its weight of sul- 

 phuric acid. During the past season I made some experiments 

 upon swedes with Peruvian guano so prepared ; and although the 

 season of 1864 was very unfavourable for roots, and the produce 

 was not more than half a good crop, the results obtained are not 

 without interest. 



Four experiments, making two pairs of two each, were made. 

 In each case 8 tons of farmyard-manure were employed per acre. 

 In the first experiment 200 lbs. of Peruvian guano, in its natural 

 state, and in the second the same amount mixed with a small 

 ■quantity of sulphuric acid, were used in addition. The third and 

 fourth experiments were, respectively, exactly the same as the first 

 *ind second, excepting that to each of them there was a further 

 addition of 2 cwts. of superphosphate of lime per acre. 200 lbs, 

 of Peruvian guano were employed per acre in each case. The 

 guano was finely sifted, and that which was to be artificially 

 prepared was well mixed with 20 lbs. of sawdust, which had been 

 previously saturated with a mixture of 12 lbs. of sulphuric acid 



