FARMERS' REGISTER— DISCOVERY OF MARL, &c. 



in the vein of the country about which I have 

 written so much. 



The specimens mentioned above, were examined, and 

 the following results obtained. 



Of the mass of argillaceous earth, (which formed an 

 unbroken cube of about seven inches,) three several sjdc- 

 cimens were taken, of near a pound each, and fromcacli 

 of these, after being pounded, smaller portions were 

 again taken for examination. To the eye, it appeared 

 that either was a fair sample of tlie argillaceous marl. 

 Of these. 

 No. 1, 100 grs. yielded 91 of carb. of lime, = 91 pr. ct. 



— 1, 300 — — 28 — — = 9J pr. ct. 



— 2,200 ~ — 24 — — z=12pr. ct. 



— 3, 400 — — 35 — — = 9i pr. ct. 

 The- mass contained several of the hard concretions 



described by Dr. M. but no portion of them was includ- 

 ed in these three samples, nor in any way served to af- 

 fect the result. Of the concretions alone, a sample 

 formed of three different lumps, yielded 64 hundredth's 

 of carbonate of lime. 



The remarkable adhesiveness of the argillaceous 

 earth, made it imjjossible to sejiarate from it (by wash- 

 ing on a filtering paper,) all the acid used — and of 

 course, all the lime dissolved in the acid, could not be . 

 removed. For this reason, any mode of examination 

 except that used (the measurement of the carbonic acid 

 gas evoh'^ed,) would have given a deceptions i-esult. The 

 same adhesiveness, and its consequences, prevented 

 an examination of the clay marl for gypsum, which 

 may well be supposed present in sufficient quantity to 

 to be useful as nmnure, in conjunction with the more 

 abundant calcareous ingredient. To determine this 

 question, we hope our friend Professor Gushing, who 

 resides near this region, will direct his attention, and re- 

 port the result of his examination. 



The crystals sent were pure sulphate of lime, (sele- 

 nite, or gypsum.) Two other samples were of mix- 

 tures of clay, with very large proportions of these crys- 

 tals, of small size: but they were not analyzed, as the 

 quantities found were stated to be too small for use as 

 manure — and the process of separation, with the im- 

 perfect means that only could have been employed, 

 would have been troublesome, and tlie result not exact. 



We hope that the small proportion of the calcareous 

 part of this marl reported, will not damp the zeal of 

 tlie discoverer, or others who can use the same means 

 for improvement. The richest parts of the bed per- 

 haps have not yet been exposed to the eye. The sour- 

 ces from which the fluid calcareous matter exudes, and 

 which concretes by age, are probably much richer ; and 

 searching for them by boring would probably repay the 

 labor. The hard lumps also may possibly be reduced 

 by time and exposure, (as hard shells are when applied 

 to acid soils,) so as greatly to increase the average rich- 

 ness of the whole quantity of the manure. But, at the 

 worst, if the manure should generally contain only ten 

 per cent, of calcareous matter, and can be cheaply ap- 

 plied in large quantities, it may be as valuable as other 

 marl of thrice its strength, but more difficult of access. 

 We regard the discovery of this mineral manure, in 

 this particular region, as holding out a prospect of the 

 most important and beneficial consequences to the agri- 

 culttu-al improvement of Virginia. — [Ed. Farm. lieg. 



Gypsiiiii frosn Smytli County, 



A friend who recently travelled through the south- 

 western part of Virginia, has brought to us for examina- 

 tion a specimen of gypsum obtained in Smyth county, 

 where, as he was informed, it is found in great quan- 

 tity. The lump before us is very pure, and of a texture 

 much more soft and yielding than the gypsum from 

 Nova Scotia, and 'therefore the more easily prepared 

 for manure. If our friend was correctly informed as to 

 the abundance of this mineral, and if facilities should 

 hereafter be afforded for its transportation, it will not 

 only prove valuable to the farmers of Smyth county, 

 but to many who arc hundreds of miles distant from 

 the quarries. 



Essay on Rotation of Crops. 



By J. Hamilton Couper. 

 From the Southern Agriculturalist. 



The difiereuce of efFect produced on the fertility 

 of the soil, by the spontaneous grov/th and by the 

 artificial culture of plants, isso strikingly con- 

 trasted, as to present itself very forcibly to all ob- 

 servant minds. Where nature is allowed to sow 

 her own seeds and to reap lier own harvests, the 

 earth, instead of being impoverished by her vege- 

 table productions, seems at each new effort but to 

 augment that fertility, which is ever presenting to 

 the eye a varied aspect of beauty and fruitfulness. 

 But very different has been the effect in most coun- 

 tries, where man has controlled the productions 

 of the soil, and limited them to those alone which 

 contribute to tlie gratification of his wants, conve- 

 niences and luxuries. Their exhaustion generally 

 follows production, and utter impoverishment 

 would succeed to teeming fertility, were not resort 

 made to benign nature, or to expensive manures, 

 to restore the lost fertility. 



Is this contrast the necessary effect of the pecu- 

 liar character of the plants which have been select- 

 ed for cultivation? is it ov/ing solely to cultiva- 

 tion; or has it arisen from a vicious system of 

 agriculture, in relation to both.'' The continued 

 and increasing fertility ot some countries, where 

 these plants are more extensively grown; and 

 where cultivation is carried to the greatest perfec- 

 tion, proves that the impaired productiveness of 

 the soil, is not necessarily the result of the two 

 first causes, whatever m,ay be their tendency ; and 

 that it is chiefly attributable to the effect of a vi- 

 cious system. 



The great error of this system has been, that 

 man, instead of following the golden maxim of 

 Lord Bacon, of conquering nature by obeying her 

 laws, has endeavored, in opposition to those laws, 

 to force her into a subservience to his own views. 

 Had he observed the changes of vegetation which 

 were spontaneously occurring arotmd him, he 

 would have perceived, that of tlie seeds of plants, 

 which are scattered with a lavish hand over the 

 earth, those to which the soil and climate v^ere 

 most congenial, and which found the greatest sup- 

 ply of food fitted to their support, obtained the 

 mastery in the contest for existence ; and continu- 

 ed to flourish, until having reduced or exhausted 

 those principles of nourishment peculiar to them- 

 selves, they al^andoned the soil to others, to which 

 it still afforded the elements of unimpaired luxuri- 

 ance. These in their turn, having occupied it for a 

 time, gave way (o more succespful rivals. Thus 



