ON DIFFERENT SOILS, 125 



say why in this locality it has succeeded, while in that its appli- 

 cation has done no good. 



d It is possible that there may be variations in the quality of 

 the gypsum itself that a difference may arise from using it, 

 burned or unburned that some samples of it may naturally 

 contain more common salt than others, since, in nature, it is 

 very commonly associated with salt ; and so on. 



In an experiment made by Arthur Young, the produce of 

 two perches of clover dressed, the one with native and the other 

 with burned gypsum, differed only by two pounds when cut 

 green.* In some countries also, as along the banks of the 

 Rhine, equal effects are said to be obtained by it in either form ; 

 while others again state, and among these M. Soquet, who has 

 made experiments on the subject,f that, on their soils, unburned 

 gypsum produced no effect whatever. 



e The weight of evidence is, I think, in favour of the idea 

 that gypsum does exercise a special action upon the green 

 clover leaf. If this be so, then even upon soils in which it 

 abounds, and which can readily and abundantly supply it to the 

 root, benefit may arise from sprinkling it over the surface of the 

 crop when its leaves have begun to cover the ground ; though, 

 if applied to the soils themselves, we could scarcely expect it to 

 do any sensible good. 



/ I only further put it as a question, whether exposure to the 

 sea may not account for the feeble action of gypsum in circum- 

 stances where we, on other grounds, should expect it to do good. 



Sea- water contains a small proportion of gypsum, and the 

 sprinkling of this water over the surface of the land, as our 

 stormy sea-winds do, may, in some places, anticipate and pre- 

 vent the natural effects of gypsum when applied to the soil by 

 the hand of man. 



Thus there are gradations in the benefit which gypsum may 

 produce. First, None at all if applied to soils which already 

 contain it abundantly, or which are watered by springs that 

 contain it, or are exposed to seas which sprinkle it over the land. 

 Second, Even on these spots, a little benefit if, instead of being 



* Annals of Agriculture) xiv., p. 319, quoted in British Husbandry. 

 f Puvis, Des di/erens Moyens d'Amender le Sol : Paris, 1837, p. 89. 



