240 BOARD OP AGRICULTURE. 



investigator made a series of similar experiments, and he found 

 that when he incorporated with the soil a small amount of 

 plaster, common salt, sulphate of soda, or nitrate of soda, the 

 quantity of water evaporated by the plant was reduced, in 

 some cases, more than fifty per cent. If he added a free al- 

 kali, like potash, I think the quantity was very strikingly di- 

 minished. I do not know the explanation of it, but every one 

 who has studied the question of the action of plaster has ac- 

 quired the conviction that plaster attracts moisture. There 

 must be some mistake about that. Plaster does not absorb 

 moisture as some other substances do, yet its effect is, when 

 incorporated with the soil, to hinder the evaporation of water 

 by the plant, and that amounts to the same thing. It enables 

 the plant to economize the water in the soil, and the water of 

 rains and dews, to a greater extent than when the soil is des- 

 titute of the substance. 



Dr. Riggs. — I would like to lay before the meeting some 

 little difficulties that I have encountered in under-draining, to 

 see if any one can account for them. I had a field about forty 

 rods lono- and twenty wide, wliich produced bulrushes and 

 bull-frogs principally, and was such an eye-sore to me that I 

 determined to drain it. I laid six under-drains, forty rods 

 long and ten paces apart, which divided the field into even 

 portions. I believe in deep drainage rather than shallow, and 

 these drains were at least three feet deep. These six drains 

 all poured their water into a main drain, that ran nearly 

 through a swale which I had previously under-drained. I put 

 in two-inch tile, and to be very nice about it, and be sure that 

 no silt or fine sand could wash into these drains, I had turf 

 turned upside down, and put over the joints, and stamped upon, 

 and a little stone placed each side of the joints to keep the 

 tile when jumped upon, from pressing one side or the other. 

 About three years after this was done the first I knew, I went 

 down to the field one day, and saw that there were streams of 

 water running in several places. I dug down to the tile, and 

 found the trouble ; and here it is. [Exhibiting a fibrous mass, 

 like jute.] I do not know what it is. I did not want to be 

 defeated in that way, so I made up my mind to take up the 



