1835.] 



FARMERS' REGISTER 



421 



in a deposite of shells, would be these: the sul- 

 phuretted hydrogen, coming into contact with the 

 atmosphere, the oxygen of the air would gradual- 

 ly unite vvilh the hydrogen and form water; sul- 

 phur would be deposited, and the. sulphuric acid 

 (of which the sulphuretted hydrogen is supposed 

 to be in part composed,) would unite with the 

 lime of the shells, forming sulphuret of lime, (or 

 gypsum) and the carbonic -acid would pass off in 

 the form of gas. The result of this process in 

 three distinct new formations, viz: water, sulphur 

 and gypsum. This theory is sustained by the fol- 

 lowing facts. 



1st. The presence of sulphate of lime, which 

 has been ascertained to exist in most of these de- 

 posites, and is believed to exist in them all. The 

 shining particles interspersed through them and 

 designated by Professor R. as mica, are most prob- 

 ably selenile, or pure gypsum. I hazard this con- 

 jecture with great distrust, and would not venture 

 it at all, if it appeared that these shining particles 

 had been separately collected and analysed by 

 him. The term mica was probably not used with 

 reference to their chemical composition, but as its 

 etymology imports, to indicate the shining charac- 

 ter of these particles; particularly as he speaks in 

 another place of one of these beds of Jersey marl 

 being interspersed with spicules of gypsum. The 

 order mica in mineralogy, is divided into eight ge- 

 nera, and a great number of species, the chemical 

 composition of each of which is different. {Ed. 

 Enc. art. Mineralogy.) And it is presumed if the 

 elements of these shining particles had been as- 

 certained by actual analysis, Professor R. would 

 have communicated the result of the process.* 



2ndly. The presence of sulphur, as indicated 

 by the strong sulphureous odor emitted by this 

 substance when gently pressed and wanned by 

 the hand, and which together with its appearance, 

 has probably obtained lor it the name, of gunpow- 

 der marl, and by the total destruction of vegeta- 

 tion occasioned by too large a dressing of it made 

 in this neighborhood, supposed to be the effect of 

 sulphur, which though highly beneficial in small, 

 in large quantities is believed to be fatal to vege- 

 tation. 



3rdly. From the remarkable fertilizing effect of 

 the gunpowder marl of New Jersey, containing 

 the green sand, and which can scarcely be attri- 

 buted to the agency of that substance alone, thirty 

 grains of which, according to the. analysis of Pro- 

 fessor R. contain of Silica 15.51 grs. 

 Protoxide of iron. 7.56 

 Potash, 3.10 

 Water, 3.00 



The most striking effects are said to have been 

 produced by the application of five loads to the 

 acre, of the gunpowder marl, containing, we will 

 suppose, in the absence of evidence, 50 per cent, 

 of the green sand. Now, according to the esti- 

 mate of the author of the Essay on Calcareous 

 Manures, of five or six bushels to the load, this 

 would be an application of 25 or 30 bushels of the 

 marl, or half that quantity of the green sand to the 

 acre, which containing about 10 per cent of pot- 



*Profcssor H. D. Rogers of Philadelphia, in his 

 "Guide to a course of lectures on Geology," states the 

 fact that gypsum is found in the Jersey mail. — Farm. 

 Reg. Vol. III. p. 200. 



ash, (the only known fertilizing principle it con- 

 tains) would makean application of 1J or 1£ bush- 

 els of that substance, or its equivalent to the acre. 

 As the effect of the protoxide of iron is entirely 

 conjectural, I leave that out of the estimate. So 

 great an effect, I apprehend, has never been at- 

 tributed to so small a quantity of potash applied in 

 any form. The green sard or '-silicate of iron and 

 potash," can scarcely be supposed capable in any 

 manner of producing this effect. Green bottle 

 glass being composed of impure materials, such 

 as river sand containing iron, and the commonest 

 kind of pearl ashes, may be considered a '-silicate 

 of iron and potash," yet we should scarcely attri- 

 bute any great fertilizing power to that" We 

 may hence conclude that the green sand is to- 

 tally inadequate, to produce, the effects attributed 

 to the gunpowder marl, and must look to some 

 other of its ingredients to explain its efficacy as a 

 fertilizing agent. 



4th. That gypsum and sulphur are the princi- 

 pal active agents in the gunpowder marl, may be 

 inferred from its remarkable efficacy on clover, ob- 

 served in New Jersey by Professor Rogers and 

 others, and by an intelligent gentleman in the 

 county of Richmond, whose statements I shall 

 subjoin. I have now before me three specimens 

 furnished by this gentleman, with a view to their 

 being transmitted to Prof. R. They all abound in 

 the shining particles which I have supposed to be 

 gypsum, and differ only slightly in color and con- 

 sistency. 



No. 1, which he designates as blue clay, abound- 

 ing with impressions of shells, without any cal- 

 careous matter, he accompanies with the follow- 

 ing statement: "In the spring of 1833, a small 

 quantity of this was beaten fine, and put on young 

 clover to see if it would act as manure. In a very 

 Cew days the difference in size and color was very 

 perceptible. In the spring of 1834 I gave the 

 whole lot of clover a top dressing of this, (say 

 300 bushels to the acre) except 15 or 20 feet run- 

 ning through the lot. This I gave a heavy dress- 

 ing of old ashes, a larger quantity than of the 

 clay. The whole lot of clover was very fine, and 

 I have never been able to discover any difference 

 in the clover, or in the wheat now growing on the 

 lot." Of No. 2, designated as yellow clay, though 

 the blue color predominates, he says: "About 250 

 bushels to the acre were put on a poor sandy knoll 

 last spring when the clover was sowed. During last 

 summer's drought, it stood and kept its color much 

 better than the lot adjoining, which had been ma- 

 nured with ashes, and the clover is now much 

 greener where the clay w r as put." No. 3, green 

 sand, corresponding very exactly to the description 

 of the pure green sand of New Jersey. "A small 

 quantity of this was put on about three feet square 

 of very indifferent clover, about three weeks since, 

 and the clover is now much greener, and at least 

 six inches higher than that adjoining it. I sup- 

 pose the quantify did not exceed two quarts." 

 (Dated 12th of June.) The effect of gypsum on 

 clover is too generally known to be now the sub- 

 ject of remark.' But'that the same effect has been 

 attributed to sulphur, and proved by actual exper- 

 iment, has not been so generally noticed, and is 

 probably unknown to a large majority of agricul- 

 turists. M. Bernard, the author of a French 

 treatise on the use of gypsum, an extract from 

 which is published in the Mem. of the Phil. Jlgr. 



