WATER SUPPLY FOR CROPS. 15 



our sewage systems water removes the wastes of civilization 

 and enables us to secure that cleanliness of person and sur- 

 roundings which is so essentially a part of civilized life. 

 It has been said " that the amount of soap used by a peo- 

 ple is an indication of the height of their civilization," but 

 is it not more properly measured by the amount of water 

 they use ? 



Water in nature is in constant motion. It is volatile at 

 all temperatures, and evaporation is continually going on 

 from the surftice of all bodies of water, as well as from the 

 soil, from vegetables and from animals. This vapor of 

 water is blown about by the winds, and condensed on cold 

 surfaces, or by colder currents of air, into clouds, and from 

 them precipitated in rain, hail or snow. A part of what 

 falls on the land flows immediately back to the ocean by 

 brooks and rivers. A larger part is absorbed by the soil, 

 and given up slowly, as it percolates through the earth and 

 escapes to the water-courses, or is taken up by the roots of 

 growing plants, or evaporated direct into the air. The soil 

 acts like a sponge, absorbing water and giving it up slowly 

 to vegetation and the atmosphere. It is with the part 

 which is absorbed and held for vegetable use by the soil, 

 that we farmers have principally to deal. The absorptive 

 power of different soils varies greatly. Some soils, by their 

 mechanical condition, absorb and hold a much larger part of 

 the rainfall than others. The annual rainfall in the New 

 Enijland and middle Atlantic States is 27 to 45 inches. 



From the report of the Chief Signal-Service Officer, I 

 find the average rainfall at Boston for ten years to be 49^ 

 inches, witli a variation of from 37|- in 1880, to 65J in 1878. 

 At Albany for seven years, the average was 38|, with a 

 variation of from 32| in 1880, to 49i in 1878. We may 

 safely take the average of these observations at the two 

 stations of Boston and Albany, as an average for the State 

 of Massachusetts. We then find the averasfe annual rainfall 

 for our State to be 44 inches, with 35 inches for 1880, which 

 was an exceptionally dry year. 



A great amount of water is required by plants to supply 

 the evaporation from their leaves. This water is all taken 

 up from the soil by the roots. The amount required 



