Chap. XVIII. AND OTHER MANURES. 307 



years.'^ In 1860 the export of nitrate of soda from the port 

 of Iquique amoimted to 1,370,248 cvrts., and a good deal 

 of borax is also exported, though its shipment is prohibited by 

 the Government. 



The extensive use of mineral substances, such as guano and 

 nitrate of soda, as a top-dressing for corn-crops, is a discovery 

 of modern times, and these manures were not generally ap- 

 preciated in England until a period between 1824 and 1829. 

 I believe that farmers consider guano and nitrate of soda to 

 be about equally efficacious as a top-dressing for corn ; and 

 it is now a matter of pressing interest to the agricultural 

 community in England to reduce their prices, which are as 

 high as twelve and sixteen pounds a ton respectively. But, 

 with this view, a careful search for deposits of guano in other 

 parts of the world has only led to the discovery of those at 

 Ichaboe, on the coast of Africa, in 1843, and of those on the 

 Arabian Kooria Mooria islands more recently. The deposit 

 at Ichaboe was all carried off by the end of 1845, while that 

 on Jibleea, one of the Kooria Moorias, is still being worked : 

 but it is very inferior to the guano of the Peruvian islands.* 



3 Bollaert's Account of Tarapaca. the rains have washed it down, and 



■• In 1858 there were 52 ships loading that it has formed a stalactitic deposit 



at the Kooria Mooria islands, off the on the surface of the rock heneath the 



coast of Arabia. In Jibleea the guano guano. A cargo of this deposit was 



is found coating nearly the whole of sliipped and sold at Liverpool for SI. a 



the island (about 500,000 tons), white ton. 



and polished, so as to be veiy slippery. The composition of Peruvian guano 



which is ver}- ilifferent fi-om the guano is as follows : — 



of Peru. lii May, 1857, this guano Water 13-73 



fi'om Jibleea island was analyzed at Organic matter and ammoniacal salts 53-16 



Bombay by Dr. Gii-aud, with the fol- Phosphates 23-48 



1 ,• • • ij. . Alkaline salts (-97 



lowmg result :— ^^^^ i-ee 



Water 6-88 i 



A2otized matter, with ammoniacal ; 100,00 



salt* 38-75 , 



Fixed alkaline salts 6- i Of Ichaboe guano : — 



1^", •-,,: 26-25 ! .^^,^jgj 24-21 



Sulphate of Ume 3.7 Organicmatter, and ammoniacal salts 39-30 



Phosphate of hrae • 18"35 i phosphates 30-00 



Alkaline salts 4-19 



Sand 2-30 



100-00 



Thus the quantit}- of phosphate of loo-oo 

 lime is very small, and it appeai-s that 



X 2 



