Proceedixgs of the Farriers* Club. 353 



periods of which the Aztec traditions tell, but was first 

 introduced into England in 1840, and into this country about 

 the same time, or a little later; it owes its highly concen- 

 trated manurial virtues to the highly organized nature of the 

 fish which constitute the food of sea birds, and the rapidity of 

 action is due to the great solubility of its constituents in water. The 

 quality even of pure guano raries greatly according to the region 

 from which it is brought ; that known as Peruvian, which comes from 

 a dry locality, c-ontaining as much as eighteen per cent of ammonia, 

 while that from locaKties subject to almost perpetual rain, and which 

 has had a considerable proportion of its most valuable constituents 

 washed away, has its worth diminished in proportion. Guanos, espe- 

 cially those containing the most ammonia, exert their most beneficial 

 action in hastening the growth of the young plant and in encouraging 

 a great expanse of foliage and growth of stem, which, by adding to 

 the jjower of the plant to absorb carbonic acid from the air, quick- 

 ens and increases the development of the plant, so that, as in the case 

 of turnips, the period during which it is liable to be attacked by 

 insects is shortened, and more than this, the time of ripening is often 

 materially advanced ; a matter of importance in many portions of our 

 own country, where the crops are liable to be nipped by early frosts. 

 It is necessary, furthermore, in order to secure the most efiicacious 

 results from the emplojniient of guano, that it should be applied at 

 those periods which may be characterized as tolerably moist and cool^ 

 and upon soils somewhat heavy and capable of retaining moisture ; 

 for, in this case, the ammonia dissolved in water will be retained in 

 the soil until absorbed by the roots of the plants ; while on the other 

 hand, if the soil be loose and porous, the soluble parts of the fer- 

 tilizer mny be washed downward by rains out of reach of the 

 plants, or if tlie weather be dry and hot and the quantities 

 of humus in the soil be limited a portion of the ammonia 

 may be volatilized and dissipated in the air. We have seen 

 that guano has an especial eflect upon plants in the early stage 

 of the growth, but the seeds of all vegetation contain a much 

 larger proportion of phosphoric acid than the leaves and the stems. 

 A large part of this may be derived from the guano, particularly when 

 phosphatic guano is employed ; but it is found good in practice to 

 assist the ripening of the plants, especially of leguminous ones, by an 

 application of more decidedly phosphatic manure, as will more fully 

 ap])ear when we come to speak of supei^jhosphates and the like.. 

 [IxsT.] 23 



