ON MANURES. 121 



farm in America, to turnips both sown along with them in the 

 drills, and spread over the plants when they got into rough 

 leaf; in each of which the superiority of the crops on those 

 portions of the land on which the gypsum had been laid, was 

 so evident in quantity, that in some patches spread with it in 

 squares, in order to mark any difference that might arise, 'the 

 ground was checkered like a floor of black and white marble, 

 and the quality was so much more sweet and juicy, that none 

 in Baltimore market sold for so much or so readily.' He 

 however admits, in another of his works, that a small quantity 

 of compost dung was laid on along with the gypsum, but 

 ' where no compost was applied, the gypsum by itself was of 

 no avail;' and in some other trials made in this country, when 

 laid upon alternate lands of oats and turnips, it has produced 

 no visible effect. In his other experiments on potatoes and 

 onions, as also on carrots and cabbages, and on various crops 

 of white corn, no perceptible difference could be observed in 

 the application of gypsum; except that, in one instance, 'the 

 plastered rows of potatoes were rather worse than the others ;' 

 and that 'on old land newly ploughed up, but not pared and 

 burnt, the gypsum was found to act as a corrector of the soil, 

 and thus to give more grain and less straw.' Mr. Parkinson, 

 indeed, attributes its chief powers to consist in its quickly 

 cementing, and thus preventing the heat of the sun from 

 exhaling the moisture or nutritious quality of the manure ; by 

 which means the plant, being kept moist at the root, conse- 

 quently grows well, and quickly gets a shade from its own 

 sprouts. This would, however, tend to prove that its applica- 

 tion would be serviceable to all crops in dry weather: an 

 opinion which is not borne out by what has been already stated 

 of its effects. 



Such are the chief p>oints regarding its practical application 

 to which some objections have been made. 1st. As tending 

 to render the land stiff" under the plough. 2d. As exhausting 

 the soil by forcing vegetation. 3d. As being confined in its 

 effects to particular crops, and becoming, perhaps, prejudicial 

 when those are followed by others of a different nature. To 

 which it may be answered : — 



1. That the increased tenacity of the soil can only be occa- 

 sioned either by some extraordinary excess in the application 

 of the gypsum, or by its being laid upon heavy clay, to which 

 it is unsuitable ; but, if applied to light porous land, unreten- 

 tive of moisture, the firmness of the texture tlius imparted 



