CHAPTER III, 



NATURAL FERTILIZERS. 



IIlIHE rocks of New Hampshire are largely granitic or feldspathic. In 

 J% decomposition an abundance of potash is liberated, together with 

 variable quantities of soda and lime. But our soils invariably show a 

 small percentage of phosphates universally distributed. As crystals of 

 apatite are uncommon, the question has often arisen in my mind, Whence 

 is this salt derived .'' We cannot believe that enough animals have left 

 their skeletons during the later periods, when the present soil was in 

 the process of formation, to explain the commonness of this essential 

 ingredient. If not of animal, it must have been of mineral origin. 



The statement has been made by prominent agriculturists, that our 

 rocks generally contain phosphate of lime. One of the points aimed at 

 in the microscopic study of our rocks has been a search for apatite, under 

 the impression that the soil phosphate must exist in minute crystals, in- 

 visible to the naked eye. Our researches have shown the presence of 

 this mineral in rocks from every part of the state. This fact gives us 

 confidence in the ability of our underlying formations to furnish from 

 age to age a plentiful supply of this salt, so essential to the growth of 

 crops. 



Part IV contains numerous incidental references to the localities of 

 microscopic apatite. I will enumerate the instances there mentioned, 

 presuming that they are much more abundant than are here indicated. 

 It occurs in the porphyritic gneiss of Antrim, the ancient gneisses of 



