132 TALKS OX MANURES. 



" Yes," said I, " and if these facts prove nothing else, they at 

 least show that there is a great difference between wheat and 

 clover. I was at Rothamsted when these experiments were 

 made. During the first nine days of the experiment, the clover- 

 plant evaporated 399.6 grains of water ; while the wheat-plant, 

 standing alongside, evaporated only 128.7 grains. In other words, 

 the clover-plant evaporated three times as much water as the 

 wheat-plant. During the next 31 days, the wheat-plant evap- 

 orated 1,267.8 grains, and the clover-plant 1,643.0 grains ; but dur- 

 ing the next 27 days, from April 28 to May 25, the wheat-plant 

 evaporated 162.4 grains of water per day, while the clover-plant 

 only evaporated 109.2 grains per day. During the next 34 days, 

 from May 25 to June 28, the wheat-plant evaporated 1,177.4 grains 

 per day, and the clover-p^nt 1,473.5 grains per day." 



" In June," said the Deacon, " the clover evaporates ten times 

 as much water per day as it did in May, How much water would 

 an acre of clover evaporate ? " 



" Let Charley figure it out," said the Doctor. " Suppose each 

 plant occupies 10 square inches of land ; there are 6,272,640 square 

 inches in an acre, and, consequently, there would be 627,264 

 clover-plants on an acre. Each plant evaporated 1,473.5 grains 

 per day, and there arc 7,000 grains in a pound." 



Charley made the calculation, and found that an acre of clover, 

 from May 25 to June 28, evaporated 528,598 Ibs. of water, or 15,- 

 547 Ibs. per day. 



A much more accurate way of ascertaining how much water an 

 acre of clover evaporates is afforded us by these experiments. 

 After the plants were cut, they were weighed and analyzed ; and 

 it being known exactly how much water each plant had given off 

 during its growth, we have all the facts necessary to tell us just 

 how much a crop of a given weight would evaporate. In brief, it 

 was found that for each pound of dry substance in the wheat- 

 plant, 247.4 Ibs. of water had been evaporated; and for each 

 pound in the clover-plant, 269.1 Ibs. 



An acre of wheat of 15 bushels per acre of grain, and an equal 

 weight of straw, would exhale during the spring and summer 

 177f tons of water, or calculated on 172 days, the duration of the 

 experiment, 2,055 Ibs. per day. 



An acre of clover that would make two tons of hay, would 

 pass off through its leaves, in 101 days, 430 tons of water, or 8,600 

 Ibs. per day more than four times as much as the wheat. 



These figures show that, from an agricultural point of view, 

 there is a great difference between wheat and clover ; and yet I 



