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It has been advantageously used in Kent, and 
various testimonies in favour of its efficacy have 
been laid before the Board of Agriculture by Mr. 
Smith. In America it is employed with signal 
success ; but in most counties of England it has 
failed, though tried in various ways, and upon dif- 
ferent crops. 
Very discordant notions have been formed as to 
the mode of operation of gypsum. It has been 
supposed by some persons to act by its power of 
attracting moisture from the air ; but this agency 
must be comparatively insignificant. When com- 
bined with water, it retains that fluid too powerfully 
to yield it to the roots of the plant, and its adhesive 
attraction for moisture is inconsiderable; the small 
quantity in which it is used likewise is a circum- 
stance hostile to this idea. 
It has been said that gypsum assists the putre- 
faction of animal substances, and the decomposition 
of manure. I have tried some experiments on this 
subject, which are contradictory to the notion. I 
mixed some minced veal with about -rio part of 
its weight of gypsum, and exposed some veal with- 
out gypsum under the same circumstances ; there 
was no difference in the time in which they began 
to putrefy ; and the process seemed to me most 
rapid in the case in which there was no gypsum 
present. I made other similar mixtures, employ- 
ing in some cases larger, and in some cases smaller 
quantities of gypsum ; and I used pigeons’ dung 
in one instance instead of flesh, and with precisely 
similar results* It certainly in no case increased 
the rapidity of putrefaction. 
