92 CALCAREOUS MANURES— PRACTICE. 



means had been used to improve, except sucli as all the land liad » eceived. 

 Within two feet of the surface the subsoil of this land is of red elay, which 

 probably helped its growth of clover. 



CHAPTER VII. 



EFFECTS OP CALCAREOUS MANURES ALONE, OR WITH GYPSUM, ON NEUTRAL SOILS. 



Proposition 5 — continued. 



Reason would teach that applications of calcareous earth alone to calca- 

 reous soils are so manifestly useless, that no more than two experiments of 

 that kind have been made by me, neither of which had any improving 

 effect that could be noticed, in the twelve ensuing years during which the 

 experiments were observed. 



When calcareous manures have been applied to neutral soils, whether 

 new or worn, no perceptible and manifest benefit has been obtained on the 

 first crop. The subsequent improvement has gradually increased, as would 

 be expected from the power of fixing manures ascribed to calcareous 

 earth. But however satisfactory these general results were to myself, they 

 are not such as could be reported in detail, with any advantage to other 

 persons. It is sufficiently difficult to make fair and accurate experiments 

 where early and remarkable results are expected. But no cultivator of a 

 farm can bestow enough care, and patient observation, to obtain true results 

 from experiments that scarcely will show their first feeble effects in several 

 years after the commencement. On a mere experimental farm, such things 

 maybe possible; but not where the main object of the farmer is profit 

 from his general and varied operations. The effects of changes of season, 

 of crops, of the mode of tillage— the auxiliary effects of other manures, and 

 many other circumstances — would serve to defeat any observations of the 

 progress of a slow improvement, though the ultimate result of the general 

 practice might be abundantly evident. 



Another cause for being unable to state with any precision the practical 

 benefit of marling neutral soils, arises from the circumstance that nearly all 

 the calcareous manure thus applied by me has been aci;ompanied by a natu- 

 ral admixture of gypsum ; and though I feel confident in ascribing some effects 

 to one, and some to the other of these two kinds of manure, yet this divi- 

 sion of operation must rest merely on opinion, and cannot be received as 

 certain by any other than him who makes and carefully observes the ex- 

 periments. Some of these applications will be described, that other per- 

 sons may draw their own conclusions from them. 



The cause of these manures being applied in conjunction was this. A 

 singular bed of marl lying under Coggins Point, and the only one within 

 a convenient distance to most of the neutral soil of that farm, contains a 

 very small proportion (perhaps about one per cent.) of gypsum, scattered 

 irregularly througli the mass, seldom visible, though sometimes and very 

 rarely to be met with in small crystals. The calcareous ingredient on a 

 general average, carefully made, was found to be 62 per cent. If this 

 manure had been used before its gypseous quality was discovered, all its 

 effects would have been ascribed to calcareous earth alone, and the most 

 erroneous opinions might thence have been formed of its mode of operation. 



What led me to susj-tect the presence of gypsum, in this bed of fossil 

 shells, was the circumstance that throughout its wliole extent, of ncai a mile 



