38 QUINCE CULTURE. 
land fertilized a long time with superphosphates, there 
is an accumulation of fertilizing material that salt makes 
available. The lime and phosphoric acid lock up what 
the salt liberates. As good results were obtained with 
one quarter salt and three quarters phosphate, as from 
all phosphate without the salt. The salt and phosphate 
in equal parts produced a fine crop of corn on a mucky 
soil. Two hundred pounds of salt on three-fourths of 
an acre gave me the best crop of German millet I ever 
grew. It will be found valuable with quinces, pears, 
plums, peaches, and apples. 
Heavy soils will usually be found to contain enough 
potash, but in an insoluble condition. Ordinarily a 
good top dressing of salt will make this potash available 
to promote a fruitful condition. The German potash 
salt, kainit, and muriate of potash will be found service- 
able to most orchards. Nitrogenous manures stimulate 
the growth of leaves more than the fruit. The mineral 
manures, such as potash and salt, aid most in perfecting 
the fruit, especially the seeds, the thing of greatest effort 
in Nature’s laboratory. 
The value of any fertilizer is determined by the amount 
of potash, phosphoric acid, and nitrogen it contains. 
Nitrogen is expensive as an ingredient in the commercial 
fertilizer, and if it can be obtained free from the air, it 
will be a very great saving to us. 
‘‘“The atmosphere is chiefly composed of oxygen and 
nitrogen ; and water, of oxygen and hydrogen; and as 
there is always in the air more or less water, the element 
hydrogen is always present. Now under certain circum- 
stances, the nitrogen and hydrogen combine in the air and 
formammonia. The oxygen and hydrogen in the air are 
supposed not to be united in a chemical combination, but 
to form merelya mixture. Hence this nitrogen is called 
the free nitrogen of the air, as distinguished from that in 
ammonia, which is not free.” 
