100 WALL'S MANUAL 



In Mr. Wilkins' experiment, one hundred pounds of 

 Peruvian guano, one hundred pounds plaster, one 

 hundred pounds salt, one hundred pounds Chesapeake 

 phosphate of lime, made an increase of seven hundred 

 and sixty -five pounds of seed cotton to the acre 

 although he lost two hundred and fifty pounds to 

 the acre by the cotton caterpillar at a cost of ten 

 dollars and fifty cents per acre, This fertilizer is 

 usually known as Dickson's preparation, and seems, 

 from experiment, to be the best proportions to mix 

 these artificial fertilizers. 



Let us examine, and see why this preparation acts 

 With such wonderful effect. By the analysis of Peru- 

 vian guano, we see it contains : organic matter, thirty- 

 six per cent. ; ammonia, seventeen per cent. ; phos- 

 phates, twenty- three and a half per cent, ; alkaline 

 salts, nine and a half per cent, [See appendix,] The 

 plaster or sulphate of lime is composed of water, 

 thirteen per cent, ; lime, thirty- three per cent, ; sul- 

 phuric acid, forty-six per cent, [See appendix,] 



The Chesapeake phosphate is bone-dust, made sol- 

 uble with sulphuric acid. 



Salt is muriatic acid and soda, 



The Peruvian guano furnishes ammonia; organic 

 matter, which is made soluble by the sulphuric acid 

 of the plaster ; phosphate, which is acted upon by 

 sulphuric acid, and alkaline salts, which are acted 

 upon by the muriatic acid in the common salt, and 

 by the sulphuric acid. 



The plaster or sulphate of lime is acted upon by the 

 muriatic acid of the salt, its sulphuric acid set free, 

 which, in turn, acts upon the bone dust or phosphate, 

 and on the organic matter of the guano, All the 



