116 AGRICULTURAL EXPERIMENT STATION. [Jan. 



No. II., covered largely with a grayish saline mass, of an 

 acid and astringent taste. Treated with water, at an ordi- 

 nary temperature, a very acid solution was obtained, which 

 contained a liberal amount of free sulphuric acid, besides a 

 considerable quantity of the combination of this acid with 

 lime (gypsum), and with oxide of iron (green copperas). 

 The presence of these compounds was evidently due to the 

 action of air and of moisture on iron pyrites, — a combina- 

 tion of sulphur and iron, — contained in the rocks and the 

 soils through which the water percolated which fills the 

 muck-bed. 



Wells located in rocks containing iron pyrites are apt to 

 show a similar alteration in their character during the earlier 

 part of the spring, after a dry summer and autumn, when, 

 in consequence of a lower level of the water supply, a more 

 extensive exposure of adjoining rocks has favored the 

 oxidation of both iron and sulphur. This change may as- 

 sume such proportions at times, that the water of these wells 

 will curdle fresh milk, and produce a more or less ink-like 

 abstract of green tea. 



A repeated pumping-out, in most instances, removes the 

 cause of these reactions. An actual observation in this direc- 

 tion at Amherst, a few years ago, after several years of dry 

 seasons, furnished a striking illustration of the previous 

 statement. 



A muck like No. III. is decidedly injurious to vegetation, 

 and needs an exceptionally large addition of lime or ashes, 

 and a longer exposure to the air than the average material 

 of this kind, to prepare it for manurial purposes. 



Sumac. 



[Waste material from Tanneries in Teabody, Mass. Sent on by the Massachusetts 

 Society for Promoting Agriculture.] 



Per cent. 



Moisture at lOOo C, 63.06 



Organic matter, 36.94 



Nitrogen in organic matter, 1.19 



Crude ash in organic matter, 6.80 



Calcium oxide in ash, 1.14 



Magnesium oxide in ash, ........ 3.2.5 



Potassium oxide in ash, .17 



Phosphoric acid, .17 



Insoluble matter in ash, 2.25 



