GUAiNO : ITS NATURE AND USE. 



471 



the conclusion, from the tables, is yet inevitable 

 that the compositioa of Guano is exceedingly 

 variable. 



It must be observed, however, that, while its 

 composition is not unifonn, it contains large 

 amounts of the earthy phosphates and the am- 

 mouiacal and alkaline salts, all of vi-hich are con- 

 sidered active manures. We maj' consider it 

 an impure compound of the phosphates of lime 

 and magnesia, and of the ammoniacal and alka- 

 line salts. 



Several attempts have been made to form ar- 

 tificial Guano — that is, to combine salt.s in such 

 proportions that the mixture shall have the same 

 properties and value as Guano. As the supply 

 of natural Guano is thought to be limited, it is 

 matter of importance to form an artificial com- 

 pound of equal value, if, indeed, the substance 

 be as valuable in Agriculture as some have rep- 

 resented. I shall add, therefore, at this place, 

 the composition of one or two specimens of arti- 

 iicial Guano. The following is that recommead- 

 ed by Petzholdt : 



Bone dust, or phosphate of lime. .^..3 cwt. 



Sulphate of ammonia ?...l cwt. 



Common salt 1 cwt. 



Sulphate of soda 10 lbs. 



Pearlash 10 lbs. 



Total 520 lbs. 



I give also the composition of Johnston's mix- 

 lure, the basis of Turnbull's artificial Guano, 

 mentioned in a succeeding table : 



Bone dust, or phosphate of lime 31.5 lbs.* 



Sulphate of ammonia 100 lbs. 



Pearlash 5 lbs. 



Common salt 100 lbs. 



Dry sulphate of soda 11 lbs. 



Total 531 lbs. 



Johnston considers this amount fully equal in 

 efficacy to 4 cwt. of Guano which cost more than 

 twice as much. 



Dr. Liebig has undertaken to reduce the same 

 principle to practice on a large scale. His ob- 

 ject is to form an artificial Guano or manure for 

 every plant. Having determined its mineral 

 constituents, and the ratio in which they enter 

 the plant, he combines on this basis various salts, 

 to form a manure suitable for the plant. The 

 mineral constituents of Havana tobacco, for in- 

 stance, may be stated as follows : 



Salts of potassa and soda 24-.30 



" Magnesia and lime 67-40 



Silica 830 



Total 100 00 



The principle is obvious and rational that 

 tliese substances, combined in the ratio of the 

 corresponding numbers, should form a sufficient 

 manure for Havana tobacco. We may safely 



7 bushels — containing 35 Iba. Am. 



(995) 



pronounce as to the correcDiess of the theory in- 

 volved, and may we not hope that experience 

 and skill will develop results of high interest 

 to Agriculture? Perhaps the introduction of 

 Guano, as a manure among us, may be of great- 

 er benefit to Agriculture, by suggesting new 

 methods of forming artificial manures, than by 

 any special use we can make of the natural sub- 

 stance. 



I shall now proceed to notice, as briefly as 

 possible, those facts which bear on the value of 

 Guano in practical Agriculture. 



Prof. Johnston says : — '• Its real origin was 

 known to the government of the Incas, and its 

 national importance fully understood. It was 

 made a capital ofience to kill the young birdoon 

 the Guano Islands." It has been used in Peru 

 for so long a period that " the memory of man 

 runneth not to the contrary'," contributing more 

 to the happiness of the people and the security 

 of Government than her richest mines. The 

 small rocky islands, Chinche, Ilo, Iza and Arica, 

 have for ages been the source of agricultural 

 wealth to the neigliboring nations. Humboldt 

 stated more than twenty years ago that " fifty 

 vessels were annuall}' loaded at Chinche alone 

 with the Guano, each trader carrying from one 

 thousand five hundred to tMO tliousand cubic 

 feet." The Peruvian farmer uses it chiefly for 

 Indian com ; and Mr. Bland, of Liverpool, who 

 has resided on the coast of Peru many years, 

 has stated — " In the valley of Chaucay, distant 

 from Lima about forty miles, a soil which, u-i/h- 

 out Guano, is capable of producing only 15 for 

 1 of Indian corn, with Guano is made to produce 

 300 for 1." It is not only employed for manure 

 in the provinces which lie along the coast, but 

 it is carried across the desert of Atacama many 

 leagues inland, " on the backs of mules, over 

 rough mountain paths, and at a great expense, 

 for the use of the agricultural districts of Peru 

 and Bolivia." Some have estimated that Peru 

 alone purchases annually ten millions of pounds 

 for her own use. 



In the United States, and especially in Great 

 Britain, many experiments have been made 

 with the view of testing the value of Guano as 

 a manure in tho.se countries. All such experi- 

 ments we shall not pretend to give, but we shall 

 notice them at some length, both witli the view 

 of directing attention to them and with the hope 

 that the Agriculturists of tlie United States may 

 be excited to greater care in testmg tliis and 

 other manures. 



Johnston in his admirable " Lectures on the 

 Applications of Chemistry and Geology to Ag- 

 riculture," has reported a large number of valu- 

 able results, obtained at the expense of much la- 

 bor and skill. Every person who desires to be 

 an intelligent farmer should have in his posses- 

 sion these " Lectures," from the press of Wiley 



