400 ANNUAL EECORD OF SCIENCE AND INDUSTRY. 



Besides the results of his own experiments, Professor Storer 

 finds proof of the lack of potash in New England soils in the 

 common impressions and practice of farmers. Good farmers 

 about Boston maintain that wood -ashes and the so-called 

 "long" horse- manure from city stables, which contains a 

 good deal of straw, are worth more than night-soil and 

 Peruvian guano. These all, except the ashes, are rich in ni- 

 trogen, and all contain phosphoric acid. The night-soil, and 

 particularly the guano, a good deal. But the night-soil and 

 guano are poor, and the ashes and strawy horse-manure rich 

 in potash. The fact, then, that on soils in the district near 

 that of the experiments ordinary practice shows the long 

 horse-manure and ashes to be more useful than guano and 

 night-soil is an additional proof of the lack of potash in these 

 soils. The guano and night-soil, with their large supplies of 

 available nitrogen, would temporarily stimulate the growth 

 of plants, but the result would be a speedy exhaustion. 

 That is to say, these fertilizers would enable the plants to 

 make speedy use of the small amount of available potash in 

 the soil; but thereafter, until the potash was re-supplied, a 

 large yield would be impossible. 



The widely prevalent opinion that, in nearly all cases, ni- 

 trogen and phosphoric acid are the only important ingre- 

 dients of commercial manures is of essentially transatlantic 

 origin. In European practice, the lack of phosphoric acid 

 and nitrogen has been felt more than that of potash. Mr. 

 Lawes, who, with Dr. Gilbert, has conducted the famous ex- 

 periments at Pothamstead, England, states that " the only 

 two substances really required in artificial manures are, first, 

 nitrogen ; second, phosphoric acid ;" and that " potash is gen- 

 erally found in sufficient quantities in soils, and the artificial 

 supply is not required." This opinion is evidently based 

 upon his own experience and observations on the other side 

 of the Atlantic. In England and on the continent of Eu- 

 rope the great bulk of commercial fertilizers are bought for 

 the phosphoric acid and nitrogen they contain, though in 

 Germany, especially, potash salts are coming into very gen- 

 eral use. 



As Professor Storer points out, the circumstances affecting 

 the amounts of plant-food in the soil in New England have 

 been different from those in Europe. Here grass and forage 



