AMERICAN INSTITUTE. 183 



lliat it was so only by making a tight bottom to the land. Through a 

 pound of powdered charcoal a million gallons of water would percolate, but 

 not one particle of decayed animal matter — and alumina in which clay lands 

 abound, was like carbon in this peculiarity. But clayey land would be 

 puddled by dews and rains if not treated rightly, and this valuable prop- 

 erty be of no use to the crop. Break up the clay into a fine powder, and 

 then the rain which holds in solution the exudations of all kinds of animal 

 substances, surrenders to it a rich burden of fertilizers ; the decay of 1858 

 is the raw material out of which the growth of 1859 is furnished. To pul- 

 verise the clay in lands heavv with it, it is necessary to back-furrow and 

 ridge them during the fall. If they have been manured, just before back- 

 furrowing, all the better — then the manure is held between the back-fur- 

 rows and the decomposition goes on all winter. The exposed surface of 

 the soil, thawing and freezing alternately, falls into powder, and not one 

 atom of the decayed manure, or of the fertilizing elements in the rain or 

 snow, is lost — the alumina retains it all, till the roots of plants in the spring 

 are ready to absorb and elaborate it. A light sandy soil, or a sandy loam, 

 lacking clay, of course, wants different treatment. That should be left 

 flat — some even roll it with benefit. A clayey loam must be treated accord- 

 ing to the amount of clay, and the crops to be raised. He would back-fur- 

 row and ridge a place into which he meant to put deep crops, but not 

 potatoes. 



Prof. Mapes enlarged upon the properties of alumina. Bury a fishy 

 duck in a clayey soil, said he, and to-morrow you may cook and eat it with- 

 out perceiving a remnant of the fishy flavor. Pulverized clay finely moist- 

 ened will disinfect a place almost equal to chloride of lime. Stables with 

 clay bottoms never smell. It was this property of absorbing and retaining 

 which made it true that farmers sometimes by carting on two inches of clay 

 upon a light sandy soil, made a barren field more productive than if the 

 same amount of manure had been spread upon it. The Professor then pro- 

 ceeded to show how land would bear to be more heavy with clay, if well 

 underdrained, than otherwise. He preferred drains five feet deep and 

 eighty feet apart to those three feet deep and twenty feet apart. Generally 

 his plan cost no more than the other. The land never puddles near the 

 drain, above the bottom of the drain. The water enters the drain from 

 below — never from the sides. Between the drains the water of falling 

 showers forms an arch in the earth, below which, for a short distance, the 

 earth is saturated, but above it never. Until this arch is flattened to the 

 lower level of the drain the water will continue to issue from the drains. 

 The five feet drain then secures two feet more of earth in depth that is 

 never saturated than the three feet drains. He urged the necessity of 

 keeping both ends of the drain open to the admission of air — the upper end 

 being secured so by a pile of large stones reaching to the surface — and the 

 circulation of air through it should be sufilcient to extinguish the light of 

 a candle placed at the upper opening. Another use of the drain was that 

 it made a mulch in effect of the upper inch of soil over the whole field. 



