CHEMISTRY AND FARMING. 307 



contain it in sufficient quantities, while the other seldom fails 

 to be rich in the calcareous elements so important to soils. 



I doubt not but the experience of the husbandmen whom I 

 address will bear corroborative testimony to the facts which 

 chemistry teaches, as it respects the value of black swampy 

 mud when applied to soils. During the extreme drought of 

 the season of 1854 much of this material was removed from 

 swampy land and spread upon soils, with the expectation that 

 it possessed some valuable fertilizing properties. It was seldom 

 that disappointment did not attend its application. It is in 

 most cases nothing but a mass of vegetable humus, leached to 

 the last degree of exhaustion by the action of water, and 

 abounds in no essential ingredient except it be carbonic acid, 

 capable of aiding in plant growth. It may be of some value 

 upon worn-out ridges, or upon a silicious plain, but upon the 

 ordinary tillage land in our section it is of but little value. 

 Generally speaking, it is not the best material for the bass of 

 compost. Those small ponds which abound in animalcules, 

 and which receive the washings of contiguous surrounding 

 hills, afford a better loam when part'.ally dried up. 



It is. of the first importance that a proper selection of soil 

 should be made upon which to ap])ly fertilizers of this descrip- 

 tion. A mass of dry sand thrown upon a spongy, damp 

 meadow, will, by supplying silex and other mineral food, and 

 by absorbing moisture, cause it to produce the finest grasses of 

 the uplands. No farmer would think of applying it to sandy 

 soils ; and it follows that it would be equally as improper to 

 apply meadow muck to soils of a moist clayey variety. Where 

 chemistry affords no positive knowledge to the farmer, much 

 judgment is needed in distributing manures upon different 

 soils. 



In the manufacture of compost, it is impossible to proceed 

 with much success without this knowledge, as in this work it is 

 not the sole object to make a simple mechanical mixture of dif- 

 ferent kinds of fertilizers, but to combine them, so that chemical 

 change will ensue, presenting barriers to the escape of valuable 

 volatile elements, and forming new compounds by the action. 

 If you develop ammonia, you must have an acid present to 

 combine with and fix it, in the form of a salt, else it is lost by 

 its extreme volatility, as has been illustrated. In making com- 



