610 SELECTIONS FROM ADDRESSES. 



four per cent, of clay in a soil renders it extremely productive, 

 and thus, where the depth of usual cultivation can be taken at 

 eight inches, a covering of this absorbing clay on the surface, 

 spread only one quarter of an inch thick and ploughed in, would 

 be an essential permanent improvement, more so indeed than 

 an equal amount of usual barnyard manure. 



This absorbing and retaining power of clay has quite re- 

 cently been published in England as a new and very important 

 discovery in agriculture, and there is every reason to believe 

 that just credit belongs to the claimant there ; but it is equally 

 certain that the same discovery was made here, after several 

 years' investigation, and published in Massachusetts some 

 months previous to the publication in England, and without 

 the slightest knowledge of what was passing there. But the 

 beneficial character of clay has long been known to the intel- 

 ligent farmer and horticulturist, although unacquainted with 

 scientific reasons for it, and even the precise mode of its absorb- 

 ing action is yet confessedly beyond the reach of science itself. 

 I have studied the subject a little and think that this absorbing 

 action is partly mechanical, dependent on the power of con- 

 traction which is eminently possessed by clay (alumina) and 

 which power it begins to exert almost immediately after its 

 chemical separation from a solution, and still exerts under the 

 most powerful heat of the furnace. By this it absorbs and 

 grasps any substance with which it may be in contact ; its mode 

 of action, however, is a question still in doubt, and requires 

 careful scientific investigation ; this it will no doubt receive at 

 the hands of those professors of agriculture who have charge 

 of these subjects in European countries, and I can only express 

 my regret that we have no institutions here where subjects of 

 like importance can be studied and investigated for the benefit 

 of the largest and really the most valuable class of our com- 

 munity, but we must be content to leave them to other coun- 

 tries. 



Having endeavored to explain the inestimable value of char- 

 coal and clay, in consequence of their powers of absorption, it 

 remains for me to show, that although clay cannot be manu- 

 factured and may be too expensive to be hauled as a manure 



