62 



THE FARMERS' REGISTER. 



are also preeeni in smaller quantity ih their fleshy 

 pans, and in iheir various fluids. 



The presence of these suVistances Iherefore 

 enables ihe guano to miiiisier to a greater number 

 of the want^ of living vegetables [han ii could do 

 were it entirely composed of uiic acid or of am- 

 monia. These latter compounds may abound 

 about the roots and leaves of planis, and yet, if 

 the phoe[)haies be wholly absent, the plant which 

 sprung up of a brii^ht green, and shot (brlh with 

 vigor, will never attain to a healthy maturity, or 

 produce an adequate return of nourishing Ibod. 



One of I he uses served by bones when applied 

 to the land is to 3 ield the phosphate of lime they 

 contain to the successive crops which are grown 

 during an entire rotation. Hence one reason why 

 the eflect of bones upon the land is in many cases 

 found to be so very permanent. The animal mai- 

 ler in bone dust vvill decompose and disappear in 

 great measure from the soil in one or two seasons, 

 but the bone earth (the phosphate of lime) re- 

 mains long in the land, is — in small quantity only, 

 and iherelbre slowly — withdrawn from the soil by 

 the crops and by other natural agencies, and thus 

 may continue to exercise a beneficial influence on 

 the fertility of the field to which it is applied lor a 

 long period of time. 



The same remarks apply to guano. On an 

 average, 150 lh>!. of guano may contain as much 

 bone earth as 100 lbs. of bones ;* and in the same 

 proportion will its action on the lanil, compared 

 with that of bones, be permanent — in eo far as 

 this ingredient is concerned. 



The fact is of great practical importance. Ni- 

 trate of soda, so much used of late and so deserv- 

 ing of more extensive trial, may be washed out of 

 the soil where the earthy part of the guano would 

 remain ; it may cease to exert a marked influence 

 after a single crop, where it is scarcely possible 

 that the phosphates of the guano should cease to 

 act ; and it may fail to bring to maturity crops of 

 corn or to fill the ripened ear, when the guano 

 would supply to the grain, among o!her sub- 

 stances, the earthy phosphates also, which the 

 eeed contains as a necessary constituent. 



While then the ammonia of the guano pro- 

 motes the early growth, its phosphates supply to 

 the ripening plant the materials which are indis- 

 pensable to its perfect developement. The ni- 

 trates a!so, like ammonia, aid in a remarkable de- 

 gree the growth of the plant in its earlier stages ; 

 but, except the potash or soda which the nitrate 

 may contain, it can supply to the maturing vege- 

 table none of the inorganic substances it is known 

 to require. Unless these are present in sufficient 

 tpiiuiiiiy in the soil, the healthy appearance of the 

 young plant, whether imparled to it by the agency 

 of ammonia or by that of nitrate of soda, cannot 

 be safely trusted to as an index of the weight of 

 corn we are lo reap, when the time of harvest 

 comes. 



4. The presence of common salt in the guano 

 need not surprise us. It is no doubt derived from 

 the sea, partly through the medium of the birds 

 themselves, and partly from the evaporation of 

 the salt spray, continually driven upon the coasts 



• Four cwt. of guano as much as 7 bushels of bones, 

 Bupposing the guano to contain about 35 per cent, of 

 phosphate of hme, which is less than the mean of the 

 specimens I examined. 



by the winds. It is variable in quantity, as we 

 should expect from a knowledge of its origin. 

 The beneficial effect of common salt when applied 

 to the land has been frequently recognized in 

 many localities and upon many soils. It no 

 doubt aid(5 the other ingredients of the guano in 

 producing its full effect upon the living vegetable. 



The important influence of guano, therefore, 

 on the vegetation equally of England and of 

 America, seems to depend upon two circumstan- 

 ces — 1st, on its containing a well-tempered mix- 

 ture of a great number of those substances which 

 the plant requires lor its perfect growth and de- 

 velopement ; and — 2J, on this admixture includ- 

 ing a considerable proportion of a substance (am- 

 monia) which in a remarkable degree hastens the 

 growth of the young plant, as well as of another 

 (phosphate of lime) which is necessary to its 

 healthy and perfect maturity. 



In the arid plains of Peru, where dews are rare 

 and rain scarcely ever falls, we can easily appre- 

 ciate the value of a substance which shall make 

 the young plant as it were rush up when a favo- 

 rable day of moisture comes, shall facilitate its 

 rapid afier-growth, and shall supply the materials 

 necessary to its perfect maturity ere the burning 

 sun and parching winds have time to scorch and 

 wither it. Uselul as it is likely to prove in our 

 climate, therefore, the beneficial effects of guano 

 may never be so striking in these latitudes as they 

 have long appeared on the shores of Peru. 



The cause, of its accumulation on the coast of 

 Peru. — Connected with this last observation is 

 the explanation of the accumulation of the guano 

 on the coast of Peru. I have already stated that, 

 according to Humboldt, it is met with only be- 

 tween the loth and 21si degrees of south latitude, 

 though the sea-lbwl are equally plentiful both to 

 the north and 10 the south of these parallels. The 

 explanation of this apparent anomaly is to bo 

 found in the climate of t.hispart of South America. 



Nearly the whole of the land along this coast, 

 between the Cordilleras and the sea, is one conti- 

 nued desert. " I have always," says Mr. Darwin,* 

 '• applied the terms barren and sterile to the plains 

 of Patagonia, yet the vegetauon there can boast 

 of spiny bushes and some tufts of grass, which is 

 absolute fi^rtility to any thing that can be seen 

 here,'' (the neighborhood ol Copiapo.) '• In Pe- 

 ru real deserts occur over wide tracts of country." 

 " It has almost become a proverb that rain never 

 falls in the lower part of Peru." " That much 

 rain does not fall is very certain, for the houses are 

 covered only with flat roofs made of hardened mud ; 

 and on the mole (at C allao) ship-loads of wheat 

 were piled up, and are thus left for weeks without 

 any shelter."! "The town of Iquique contains 

 about 1000 inhabitants, and stands on a little plain 

 of sand at the fool of a great wall of rock 2000 feet 

 in height, which here forms the coast: the whole 

 is utterly desert. A light shower of rain falls only 

 once in very many years ; and hence the ravines 

 are filled with detritus, and the mountain sides 

 covered by piles of fine white sand, even a thou- 

 sand feet high."J 



It is the dryness of the c'imate then which has 

 permitted the guano to accumulate on these 

 coasts. When we reach a region in which from 



• Researches in Geology and Nat. History, p. 428. 

 t Ibid. p. 446. t Ibid. 442. 



