(500 The Loir, H'ccdon Plan of Groivin// Wheat. 



between the results oi tlie three experimenters on eaeh of tlic 

 fourteen soils. Aeeordinn^ly there is jj^iven the following Table : — 



///, IIk; upper portion, the percentages of nitrogen in each soil, 

 as found by each of the three chemists, and calculated upon the 

 soil dii(!d at l{)ir C. (210'' F.), are given. And— 



In the loiver portion of tlie Table, the calculated lbs. of am- 

 monia per acre of 4,000,000 lbs.* of dry soil, according to the 

 determinations of each separate experimenter, and also according 

 to the mean of the three, are given. And in the last column are 

 given, the lijs. j)er acre of ammonia for each soil as calculatctl by 

 liaron Liebig, 



So discrepant arc the determinations of the three separate 

 experimenters on the same soil in almost every case, that the results 

 must be considered quite inapplicable as a means of arranging 

 the soils according to their probable; relative amounts of nitrogen. 

 So great, indeed, is the (liscr(q)ancy, tliat we fmd frequently once 

 and a half or twic e as umcli, and in s(!veral instances even ten limes 

 as nmch, recorded by one chemist as by another, for one and the 

 same soil. In fact, in applying each of the separate analyses 

 instead of the mean of the three, to estimate the amount of nitrogen 

 or ammonia per acre, we find that one or two of the soils could 

 be put both at the toj) and nearly at the bottom of liaron Liebig's 

 list, accordingly as we sch^ct the determination of <me or another 

 of the experimenters; whilst in the same way, several others 

 might be separated from one another by half the items in the 

 list. It may even be a question, how far a judgment can be 

 formed from such results, of the probable average or range of 

 amount of nitrogen in the soils. 



It is, however, only due to Professor Magnus, the able and 

 conscientious re])orter to the lloyal College of Rural J'^conomy in 

 Berlin, of the analyses in which these nitrogen determinations 

 are but items, to say that he called particular attention to the 

 little agreement between the results of the different experi- 

 menters. In fact, his chief conclusion was, that as twenty-one 

 of tlu! best chemists in Germany, or of those working under the 

 superintendence of the most distinguished chemists, had been 

 selected, and as there could therefore be no want of technical 

 knowledge devoted to the subject, it was obvious that in the 

 existing state of science little was to l)e expected from the analysis 

 of soils. 



* The estimate of 4,000,000 lbs. of dry soil per acre, taken to the depth of one 

 foot, is higher than we have l)een accustomed to take it ; but v.-e adopt it here, not 

 only l)ecause it is a convi-nient round number, but becausu it obviously agrees very 

 closely with the amount sup[)osed by Haron Lirbig. with whose estimates we. are 

 comparing our own figures. It is obvious that the cubic contents, and the weight 

 of (Wdildl'lc soil on an acre, must vary extrenu'ly ; so that any figure adopted in 

 an estimate of this kind must b'j to a gr(;at e.xtcnt arbitrary. 



