On Guano. 



321 



fairly tried against the guano ;* because it does not appear, as 

 some have been led to believe, that the supply of this substance 

 on the coast of Peru is by any means inexhaustible. 



According to Mr. Winterieldt the supply of recent guano has 

 diminished materially even in recent times ; and in an extract 

 from his letter already given he mentions one extensive deposit 

 of the old guano in the island of Iqurque, which was exhausted 

 in 25 years by the local consumption only. 



But the diminution is placed in a stronger light by Mariano 

 de Rivero, in a paper published in the Spanish language, but 

 from which an extract is given in Ferussac's Bulletin (sec. I.j 

 torn, xi., p. 84). He says — • 



" The Spaniards permitted the wise ordinances of the Incas, which 

 ensured the preservation of this valuable manure, to he entirely for- 

 gotten. The Peruvians are now aware of this great error, and see with 

 anxiety the period approaching when the guano will no longer be ob- 

 tained in sufficient quantity to meet the demands of the agriculture of 

 the country. The discovery of neiv deposits of the hrown guano, ichich 

 is of very ancient origin, is daily becoming more rare, while the produc- 

 tion of the recent white guano is rapidly diminishing, since, through the 

 freedom of commerce, so many vessels have visited the coast and scared 

 the birds which frequented them."t 



If the above account is correct, it is the interest of Peru to 

 prohibit the exportation of the guano ; but the introduction of it 

 into this country in the mean time will prove a great national 

 service, if it shall teach us to imitate so valuable a natural pro- 

 duction, and, by making available those articles of home manufac- 

 ture w^hich have hitherto been neglected by the agriculturist, to 

 supply the lack of farm-yard manure, and thereby to raise a 

 greater amount of food than we should otherwise be able to do. 

 Thus at the same time will the chemical arts and the art of cul- 

 ture be bound together by still another tie, and the mutual 

 dependence of all classes of the community, however apparently 

 distinct their industrial occupations, be still more distinctly 

 illustrated. 



Durham, 20th October, 1841. 



* I have not suggested the comparative trial of such substances as those 

 sold under the name of urate, animalized carbon, &c., because, though I have 

 no doubt of their efficacy when prepared after a certain manner, yet the 

 practical farmer h?s no guarantee that what he purchases this year shall 

 prove equal in virtue to that which he applied to his land in a former season. 



t See Poggendorfs Annalen, vol. xxi. p. 606. 



VOL. II. 



