On Guano. 



317 



proportion as the exact experimental farmer shall become satisfied 

 that the use of it is attended with profit to himself. 



Every man has a right to a fair return for his own labour, and 

 to an adequate compensation for pecuniary risk ; and those persons 

 deserve especial compensation who have hazarded their money in 

 importing a substance which, like guano, may minister to the 

 most vital wants of the country; but those who, having themselves 

 no pecuniary interest in practical farming, are yet desirous, as 

 good citizens, to promote the growth of food as the foundation of 

 national prosperity, may be excused in considering the chance of 

 great profits to speculators, as subordinate to the general interests 

 of the agriculture of the country. 



III. Let us then advert to theory, and see the highest price 

 which, according to its indications, the farmer ought to be called 

 upon to pay for the guano. 



We have seen that this substance is a mixture of various che- 

 mical compounds. It is a natural mixture : but an artificial 

 mixture may be made which shall more or less completely imitate 

 it. What would such a mixture cost at the present price of the 

 several ingredients of which it consists ? The phosphate of lime 

 it contains exists abundantly in bones : the ammonia may be 

 applied either in the form of sulphate of ammonia or of sal am- 

 moniac, both of which are low in price : the common salt and 

 sulphate of soda can be obtained at little cost ; and the urea, 

 being so small in quantity, may be either neglected alogether, or 

 may be replaced by a little dried urine or night-soil (Poiteviu's 

 manure). A mixture of this kind, equal in virtue to 4 cwt. of 

 guano, would cost as follows : — 



315 lbs. or 7 bushels of bone-dust, at 25. 9c?. . . £0 19 3 

 100 lbs. of sulphate of ammonia, containing 34 lbs. of 



ammonia , . . . . . 0 15 0* 



5 lbs. of pearlash 0 0 10 



100 lbs. of common salt . .... 0 2 0 



10 lbs. of dry sulphate of soda . . . . 0 0 10 



530 lbs. 5 equal to 4 cwt. of guano. £l 17 11 



To these it miffht be advisable to add 100 lbs. of chalk to aid 

 in gradually converting the sulphate of ammonia into carbonate, 

 in which state it may possibly be more immediately active 

 upon the plant. This, however, is a matter for trial, as I am 



* At the pleasme of the experimenter, a portion of the sulphate of am- 

 monia may he replaced by nitrate of potash, in the proportion of about three 

 of the nitrate to two of the sulphate. 



