384 



Nitrate of Soda as a Manure. 



nine years^ It is true that the Admiral's survey has been 

 limited to the middle district^ the Chincha Islands, and that, 

 according to the Peruvian government, the northern and southern 

 districts contain 8,000,000 tons of guano besides. But when we 

 have made due allowance for the airy amplitude of Spanish 

 arithmetic, and also a deduction for inferior quality from the 

 gross quantities which English officers may find in existence, it 

 is to be feared that those other districts may not add many years 

 to our lease of this valuable manure. The prospect is formidable, 

 since 150,000 tons of guano are now imported yearly, and nearly 

 a million and a half sterling expended by spirited English and 

 Scotch farmers, whose management is entirely dependent upon 

 this foreign manure. We must now, therefore, look the difficulty 

 in the face and prepare for the emergency. A fresh source of 

 supply is of course desired, and our vessels are on the look-out 

 for one ; but the samples of new guano lately brought home 

 have been found deficient in the essential ingredient Nitrogen. 

 One guano, indeed, met with, how extensively seems doubtful, 

 in island caves of the Indian Archipelago and on the coast of 

 Tenasserim, and produced not by seafowl but bats, does contain 

 Nitrogen, not indeed as ammonia but as saltpetre. This trans- 

 muted guano, used successfully in the spice plantations of Penang, 

 contains a warning, as it were, that, instead of merely searching 

 the seas, with whatever hope, for more guano, we should at 

 once recognise the most valuable ingredient of guano as it is 

 found for the digging on the vast salt-plains of Tamarugal, at 

 the foot of the Andes. The supply, too, of Nitrate is likely to 

 increase, not diminish, for, since attention was drawn in this 

 Journal last winter to its manuring efficacy, an engineer has pro- 

 ceeded from England to construct a railway from the port of 

 Tquique. It may be useful then to conclude this short notice by 

 a comparison between guano and cubic saltpetre, as applicable 

 and applied to particular crops ; and if any one imagines that 

 guano belongs only to amateur farming, Mr. Stevenson will tell 

 him that in East Lothian* the money expended on portable 

 manures may be taken at 12^. to 18-s. per acre on the whole 

 cultivated land of the county, that from 400/. to 600/. is a common 

 yearly expenditure for guano on individual farms, and that " the 

 largest acreable produce known to him is from land naturally very 

 inferior, a cold retentive clay resting upon the coal formation" — 

 the worst of all subsoils — 205. per acre rent being paid to the 

 landlord, but to the guano-merchant 46^. per acre, or a thousand 

 pounds yearly. 



In comparing the two manures we must not, of course, 



* See Keport on East Lothian in the present number, p. 304. 



