224: HOW CROPS GEOW. 



ods employed by him, though the best in use at that day, 

 . and handled by him with great skill, were not adapted to 

 furnish results trustworthy in all particulars. Fourteen 

 years later, Arendt* at Moeckern, and Bretschneiderf at 

 Saarau, in Germany, at the same time, but independently 

 of each other, resumed the subject, and to their labors 

 the subjoined figures and conclusions are due. 



Here follows a statement of the Periods at which the 

 plants weVe taken for analysis : 



tstill closed, 

 lot -poTinri 1 June 18, Aieiidt— Three lower leaves unfolded, two upper 

 ibb i-Biiou! „ 19, Bretschneider— Four to five leaves developed. 

 9H -poi-iriri I Juue 30, (12 days), Arendt— Shortly before full heading, 

 .iu jreiiou J „ 29, (10 days), Bretschneider— The plants were headed, 

 a/i T>o^«/ilJuly 10, (10 days), Arendt — Immediately after bloom, 

 da renoaj „ 8, ( 9 days), Bretschneider— Full bloom. 

 itvi Poriorl I July 21, (11 days), Arendt— Beginning to ripen. 

 4tn i-eiioa j „ gs, (20 days), Bretschneider— " 

 •itYi VorioiilJuly 31, (10 days), Arendt— Fully ripe, 

 otn renoa j ^^^ g_ ^ g days), Bretschneider— Fully ripe. 



It will be seen that the periods, though differing some- 

 what as to time, correspond almost perfectly in regard to 

 the development of the plants. It must be mentioned 

 that Arendt carefully selected luxuriant plants of .equal 

 size, so as to analyze a uniform material (see p. 171), 

 and took no account of the yield of agiven surface of soil. 

 Bretsclineider, on the other hand, examined the entire 

 produce of a square rod. The former procedure is best 

 adapted to study the composition of the well-nourished 

 individual plant; the latter gives a truer view of the crop. 



The unlike character of the material as'just indicated 

 is but one of the various causes which might render the 

 two series of observations discrepant. Thus, differences 

 in soil, weather and seeding, would necessarily influence 

 the relative as well as the absolute development of the two 

 crops. The results are, notwithstanding, strikingly ac- 

 cordant in many particulars. In all cases the roots were 

 not and could not be included in the investigation, as it 

 is impossible to free them from adhering soil. 



* Das Wachsthum der Haferpflanze, Leipzig, 1859. 



iWachsthumsverhaltnisse der Haferpflanze, Jour, fur Prakt. Chem,, 76, 

 193. . 



