GRIMSLEY.]| — Gypsum as a Fertilizer. 129 
From Indiana the following report was made : 
‘Tn 1892 I sowed plaster with corn, dropping a little plaster in each hill, and 
obtaining a large crop from the same. This year (1893) I put the same land to 
clover, with no plaster or other fertilizer, and now, wherever there was a hill of 
corn last year, the clover has grown six inches higher than the rest of the field.”’ 
Theories of the Action of Gypsum as a Fertilizer. 
All these various experiments, with their favorable results, 
and very many others, which have been related by farmers who 
have made practical use of gypsum, show beyond any doubt 
that on certain soils and for certain crops, gypsum is a valuable 
fertilizer, but it is not valuable for all soils‘nor for all crops. 
Various theories have been advanced to explain the action of 
gypsum on plants. Some of these are very crude and have long 
been set aside, but it will be interesting to recall them. Certain 
plants are benefited by use of gypsum plaster, and first the 
chemical composition of some of these plants will be examined. 
The examination of the ash of plants was made long ago, and 
formed the basis for a number of theories about the action of 
plaster on plants, especially for those theories which regarded 
gypsum as adirect element of plant food. The following tables 
are taken from Johnson’s excellent book entitled ‘‘ How Crops 
Grow,’’ and give the parts in 1000: 
ANALYSES OF PLANTS. 
Z, ne rd RN Su ae) Rn oe) Q 
S| 2) 8) ee |e lela ie) 
ei Ss ie |e Pe pe lS Peel ee si 2 
e rs eras SO gece ana 5 
: 5 : mS 3 2 i.8 Bei @ 
. ° : ss . 5 ° 
Rasturer crass eee eee 782 UWB | Blea |] Bail 0.3] 2.6 2 1.9} 0.7 4.1 2.1 
Red clover, young.......... 860 GO} TO} Boalt O23 |) BO] Wo yy. wet | O83 |) On4) yO. 
hy ihm lMC! sso00 co0e 820 Ne MeN Bo Oo hosp LLG IP Thos Ooeb Deeb) Oaks 
Sie in flower...... 800 AB ty WBA I Bob Oo 4b | Uo TB Ook Wodk Oaks 
Alfalfa (early flower) ...... 740 CoN? W2 AH OB Bid] OO 21.6} Wel |) Le Oe 
hite clover, in flower ....| 805 Ho MB Bolt ALO} 48 ob LS ot 6 @.6 4 Os 
ROTO JOEINE cos 00000000008 750 3.4 Oo } oS 1) 0.8) OB Osh ALG] Os | O@s2 |) Os 
ONES (GARDEN) 0 c600000000 0000 1439 ele On| icon eee On Os. tn La OM leo iG. Siitm Ono tel Oko ln Ons 
Miaizen(craim)heeneacerceienc 144 16.0 12.4) 3.7 0.1 OF3 1.9 5.7 0.1 0.3} 0.9 
Spring wheat (grain) ...... 1S} |] 20] 18], B68), O84) OH | B24} OO} O24 Os  OpF1 
Winter wheat (grain)...... MYL PADS) |} WIS) |] Wor 1} Os |) Web AlN i Wo) Wek) Wed) | War 
Garden bean (seed) ........ 150) BO I eA AS I AT seb I hows I ote Dot We aE I Wsea il ee) 
THEORY OF DE CANDOLLE AND CHAPTAL. 
An early theory to explain the action of gypsum on soils, very 
attractive and popular in its day, was that of De Candolle, who 
