1900.] 



PUBLIC DOCUMENT — No. 33. 



69 



treatment. Three hundred grams of the air-dried soils were 

 taken and put into a cylinder three inches wide and six inches 

 high, with a perforated bottom, over which there was placed 

 a layer of tilter paper. The cans containing the soil were 

 then weighed, after which the samples were liberally treated 

 with water until they contained all that was possible for them 

 to hold. The cylinders were then set aside, and after the 

 w^ater had stopped dripping they were again weighed, and 

 the additional weight which was due to the amount of water 

 applied was noted. This represented the amount of water 

 which the soils could retain. Other air-dried samples of the 

 same soil were heated in an oven to perfect dryness, and by 

 this means the amount of hygroscopic water was dbtained for 

 each. This, being added to the amount of water retained, 

 gave the total water capacity of the soil ; and, dividing this 

 sum by the weight of water- free soil, which was obtained by 

 subtracting the hygroscopic water from the original three 

 hundred grams, we obtain the percentage of water which each 

 soil is capable of retaining ; or, in other words, 



Water retained + Hygroscopic water ^ of water-retain- 

 Water-free soil 

 ing capacity. 



The following table gives the results of these experiments 

 in the order of water-retaining capacity : — 



Table V. — Shoiving the Retentivity of Soil Moistures in Order of 

 Retaining Capacity. 



As might be expected, the coast soils show the smallest 

 percentage of water-retaining capacity, and this percentage 



