702 



POPULAR SCIENCE MONTHLY. 



two positions is only for temporaiy rest. 

 No permanent foothold can ever be 

 gained on such a foundation of quick- 

 sand. An impassable dead line in bib- 

 lical study is indicative of the theologi- 

 cal and not the scientific method. 



Lewis Dayton Burdick. 



McDONOUGH, N. Y. 



A CORRECTION". 



Editor Popular Science AfontMij : 



Sir: A correspondent, Mr. C. Wood 

 DaA'is, of Peotone, Kansas, appears to 

 think it his duty to prove that we can 

 not produce wheat enough in this coun- 

 try to meet our own future demands, 

 and apparently regards it as a personal 

 matter when any one contests this posi- 

 tion. He also thinks he has found a 

 small error in long division in the last 

 article which you printed from me on 

 this question which I can not find, but 

 which if found and corrected would 

 have no influence on the genei'al argu- 

 ment. 



He also rebukes me in a most ear- 

 nest manner for the alleged misuse of 

 the chemical term " phosphate of pot- 

 ash," which crept into my article in con- 

 nection with the right use of the term 

 " phosphate of lime," when I referred to 

 the mineral phosphates of Kentucky, 

 Tennessee, and Florida. Technically he 

 is apparentlj^ right. There is no perma- 

 nent form or no natural mineral form 

 of phosphate of potash which can be re- 

 moved from place to place. Yet my ar- 

 ticle was revised by an experienced 

 geologist, thoroughly familiar with the 

 chemistry of the soil, before I sent it to 

 you, and he failed to correct this tech- 

 nical error. ]\Iy own knowledge of 

 chemistry is very limited. 



It might be inferred, as my irascible 

 correspondent points out, from the man- 

 ner in which I have called attention to 

 the deposits of mineral phosphates in 

 Kentucky and Tennessee, that I thought 

 these deposits woidd yield ])hosphates 

 of lime and phosphates of potash each 

 in a separate movable form, wliich could 

 not be a fact. Yet my critic will doubt- 

 less admit that the soils of many parts 

 of this country are stocked with potash 

 suflicient for a very long period. 



Many years ago, when I began the 



study of the cotton plant and its growth, 

 under the leadership of the late Prof. 

 William B. Rogers, I made reference to 

 the existence of the vast supplies of 

 phosphate of lime and potash, which are 

 necessary to the growth of the cotton 

 plant, in the Southern soils. I derived 

 my conception of their origin in the low- 

 lands and plateaus in marine formations 

 from Professor Rogers, and also from 

 the works of Professor Shaler, One may 

 also impute the large amount of potash 

 that is found in the valleys and moun- 

 tain lands to the disintegration of the 

 gneiss and other rocks of the Appala- 

 chian chain, which have never been 

 washed out by glacial action or by gla- 

 cial streams. If any one has been mis- 

 led by this slight misuse of chemical 

 terms it may be well to state that phos- 

 phate of potash does not exist, and I 

 am told that it can not exist, in a sepa- 

 rate removable form. 



We have not as yet discovered any 

 large deposit or mine like that of Stass- 

 furt, in Prussia, yielding potash in a 

 commercial form in which it can be 

 widely distributed. We import annu- 

 ally thousands of tons of potash from 

 Stassfurt. This deposit was discovered, 

 as I am informed, by accident, and it 

 may be hoped that a similar accident 

 may occur in this country. These mines 

 were originally opened for the produc- 

 tion of salt. In boring for salt the prod- 

 uct of a stratum above or below the salt, 

 I know not which, was brought up, 

 which was thrown aside as worthless 

 until an inquisitive visiting chemist ex- 

 amined it and thus discovered this great 

 source of potash. We possess enormous 

 beds of salt, of soda, and of alkalies, 

 scattered throughout the area of this 

 country, in connection with which it 

 may be hoped that we may hereafter 

 discover a cleposit of mineral potash, or 

 of the mineral from which potash may 

 be derived cheaply and in large quan- 

 tities. 



These two exceptions which have 

 been taken to my article have no real 

 connection with the substance of the 

 argument, which stands independently 

 eitlier of the undiscoverable error in 

 long division or of the technical fault in 

 the use of the term " phosphate of pot- 

 ash." Yours very truly, 



Edward Atkinson. 

 Boston, June 7, 1S90. 



