458 VALUE OF GUANO AS A MANURE. 



per cent. 



Phosphate of lime 25 



Ammonia, phosphate of magnesia, phosphate of ammonia, & ox- 

 alate of ammonia, containing from 4 to 9 per cent, of ammonia. 13 

 Siliceous matter from the crops of the birds 1 



100* 

 Others have found sand in much larger proportion than was pre? 

 sent in the samples examined by myself— while it may, I think, be 

 taken for granted that very little of what comes to this country is so 

 rich in sokible matter, containing ammonia or its elements, as is re- 

 presented by the analyses of Dr. Ure.f 



Variable as its composition is, however, there is now no doubt that 

 any of the samples yet brought into the English market may be ad- 

 vantageously applied as a manure to almost any crop. From the 

 most remote period guano has been the chief manure appHed to the 

 land on the parched shores of Peru — and at the present day it is not 

 only employed for the same purpose in the provinces which lie along 

 the coast, but it is also carried across the desert of Atacama many 

 leagues inland, " on the backs of mules over rough mountain paths, 

 ancTat a great expense, f^ the use of the agricultural districts of 

 Peru and Bolivia" (Silliman's Journal, xliv., p. 10.) It has been 

 estimated that a hundred thousand quintals (the quintal is equal to 

 lOli lbs. avoirdupois) are, at the present day, annually sold in Peru. 

 There also the quantity and the price vary — tbe recent white guano 

 selling usually at 3s. 6d., the more recent red and grey varieties at 

 2s. 3d. per cwt. (Winterfeldt.)| In this country, the latter — the only 

 variety yet imported — sells at present (1843) at about 10s. a cwt. 



In regard to the effects of guano upon various crops, many import- 

 ant experimental results, obtained in 1842, will be found in the Ap- 

 pendix. I here insert a few of the more important of these, along 

 with some others made in the more southern counties, which appear 

 to be highly deserving of consideration. 



Swedish Turnips. 



Produce per acre. 

 "Top-dressed with tons. cwt. Locality. 



'°-^::r'.''^'fl'::t: ll ^^Baroch,„,„earPaisley. 



2°. Farm-yard dung.20 tons. 16 18 J 



Guano§ 2\ cwt. 17 4 > Parish of Wraxal, Somerset. 



Bones... 32 bush. 15 17) 



• By way of comparison, I insert here the approximate composition of the solid part of 

 the excrements of four different varieties of eagle, as determined by Coindet : — 



American American Grand Duke 



Senegal Eagle. Hunting Eagle. Fishing Eagle. of Virginia. 



Uric acid 89 79 9037 84 65 8871 



Ammonia 785 8-87 9 20 8-55 



Phosphate of lime 2-36 0i6 6 15 2*74 



100 100 100 100(a) 



(o) Gmelin Handbuch der Chemie, II., p. 1456. 



tThe presence of ammonia in guano is readily ascertained by mixing it with a little 

 slaked lime— when the odour of ammonia will be immediately perceived, and will be 

 strong in proportion to the quantity contained in the guano. 



t For further particulars regarding guano the reader is referred to a paper in the Journal 

 of the Royal Agricultural Society, II., p. 301. 



§ Mixed with 1 cwt. of charcoal powder. 



