THE SOUTHERN PLANTER. 



53 



the result of the Doctor's experiments. He also 

 notices the fact, attested by Mr. Ruffin, Mr. Pur- 

 vis, and Sir John Sinclair, that the atmosphere 

 incumbent upon limed lands is always a healthy 

 one. He calls to mind, also, the well known 

 circumstance, that low, wet lands, where the 

 cultivated plants present a pale, sickly appear- 

 ance, are also the generators of that class of 

 diseases, known as bilious. From these cir- 

 cumstances, the Doctor infers that the healthi- 

 ness of the atmosphere is intimately connected, 

 in some way, with the power of plants to reflect 

 the green ray of light. We would again re- 

 spectfully inquire, if the old idea, that the vigor 

 of the plant, evidenced by its greenness, promotes 

 the wholesomeness of the atmosphere by its in- 

 creased consumption of the deleterious carbonic 

 acid expelled from the lungs of animals, is not 

 as reasonable as the more novel hypothesis of 

 Dr. Wight. 



But we have probably already devoted greater 

 space, than will be agreeable to our readers, to j 

 this theory of the Doctor's. We will, therefore 

 conclude by extracting what the Doctor, whom j 

 we know to be a practical man, declares to be 

 the practical rules, to which his observations and 

 experience have brought him: 



"1st. That as the growth and nourishment of 

 plants appear to be alike dependant on the re- 

 sults of the decay of organic, or animal and ve- 

 getable matters, and upon those inorganic sub- 

 stances which increase their action upon the 

 light, w 7 e are thus admonished of the necessity, 

 the absolute, indispensable necessity, of periodi- 

 cally restoring to the soil, an amount of both 

 those elements corresponding with that which 

 is taken from it by cropping. If one of those 

 elements only be returned, the productive powers 

 of plants will not be developed to the extent of 

 which they are susceptible. If both be with- 

 held, the soil must, and will deteriorate, because 

 plants are thus deprived of the means by which 

 they live, and grow. Both, then, are essential 

 to the corruption of decayed plants, the leaven 

 of the salts must be added, to give rise to forms 

 of the highest beauty and usefulness. The su- 

 periority of animal, or putrescent manures, as 

 they are termed, over those of vegetable origin, 

 is owing solely, it is conceived, to the alkaline 

 salts, which the former contain. But as in these, 

 the ammoniacal, or volatile salts predominate, 

 their effects are necessarily transient, and hence 

 the utility and economy of using those of more 

 fixed character, as lime and ashes. As regards 

 the quantity of alkaline earths, or salts of lime, 

 to be applied to an acre of land, my own expe- 

 rience does not enable me to decide. But is it 



not reasonable to suppose, that this question, as 

 far as it relates to the action on the light, should 

 be determined by their solubility % It is well 

 known that plants can take up nothing except 

 in the form of solution, and we have abundant 

 evidence going to show that the effects of fifty 

 or a hundred bushels of lime or ashes, have 

 been distinctly visible for an equal number of 

 years. Hence it would appear that the quan- 

 tity of rain, which falls upon an acre of land, is 

 not adequate to dissolve more than a bushel of 

 these substances. If it were otherwise, if more 

 were dissolved, plants would certainly take up 

 a larger quantity, and the effects would neces- 

 sarily be less permanent. If, then, this mode of 

 reasoning be correct, a bushel of either of these 

 salts enumerated, or what would be far prefera- 

 ble, as they all have their peculiarities of action, 

 a bushel of each will be fully sufficient for the 

 attainment of their direct influence. To secure 

 their indirect benefits in loosening the soil, and 

 rendering it more permeable to atmospheric in- 

 fluences, thus alleviating human toil, a much 

 larger quantity will, of course, be "required. Is 

 the question here asked, whence is the magical 

 influence of plaster compared with the other 

 salts of lime if they act upon the same general 

 principle? — the answer seems to be that it is 

 referrable to its superior power of increasing the 

 action of plants upon the light. Thus the ex- 

 periments of Sir Isaac Newton have shown that 

 bodies of an unctuous, or sulphureous nature, 

 have a greater relative refractive power, than 

 others, or than their densities indicate. Plaster 

 is a sulphate of lime, consisting of sulphur, oxy- 

 gen and lime. May we not hence fairly infer 

 that it is the subtle influence of the sulphureous 

 principle, upon that all important agent, light, 

 which enables plaster to produce an effect ap- 

 parently so vastly disproportioned to the cause* 

 Consistently with this view the acknowledged 

 pre-eminence of plaster and clover in the rapid 

 improvement of land may be explained by the 

 superior refractive power of the former acting 

 through an appropriate medium in the broad 

 leaf of the latter. Hence it is also that its 

 powers are still more conspicuous in the tobacco 

 plant and the pumpkin vine ; its apparent bene- 

 ficial effect being proportioned to the extent of 

 surface through which its influence is exerted. 

 Indeed, without the aid of those substances, 

 which increase the action of plants upon the 

 light, the broad leaves may be supposed to be 

 less adapted to the purposes of profit and im- 

 provement than the narrow leaved, since the 

 operation of nature, a constant and close relation 



( * Even admitting- with Liebig that on the applica- 

 tion of plaster a double decomposition ensues, whence 

 results carbonate of lime and sulphate of ammonia, 

 still the singular properties of plaster may be as- 

 cribed to the increased action in the light which the 

 sulphureous principle is known to impart. 



