THE ASH CONSTITUENTS OF PLANTS; THEIR ESTIMATION 

 AND THEIR IMPORTANCE TO AGRICULTURAL CHEMISTRY 

 AND AGRICULTURE. 



B. TOLLENS, Ph. D., 

 Director of the Agricultural-Chemical Laboratory, University of G'dttingen. 



Part I. — The Ash of Plants, its Preparation and Analysis. 



Regarding the origin and importance of the residue remaining after 

 the burning of plants, i. e., the ash elements or "the salts," strange 

 theories were held in the first part of the nineteenth century, even 

 among many of the learned men of that time. At the close of the 

 eighteenth century Theodore de Saussure had demonstrated the soil 

 in which the plants grow to be the source from which the ash elements 

 are derived, and clearly showed these elements to be indispensable to 

 the life of plants. Although his theoiy received the support of the 

 chemists of that day, as Davy and Berzelius, it was not until after 

 iSiO that its truth became generally accepted. About that time 

 Bc^ussingault ^ in France and Liebig ^ in Germany based their cele- 

 brated writings upon those of de Saussure^ and the fundamental 

 researches of Wiegmann and Polstorff.* The importance of the ash 

 constituents of plants and their study was soon very generally con- 

 ceded by agriculturists as well as by others, and now the matter is 

 accepted be3^ond an}^ doubt. 



De Saussure attempted the most careful estimation of the ash ele- 

 ments of. plants, not only the total amount of ash, but also the 

 quantities of the individual constituents; and these determinations by 

 improved methods have been made extensively ever since. When 

 regard is had to absolute accuracy, ash analysis is not as simple as 

 might at first appear, or as some chemists who have given little atten- 

 tion to the subject are inclined to regard it. On the contrary, it 

 requires the exercise of special precautions, as Strecker,^ among 



' Economie rurale, 1844. 



^ Die Chemie in ihrer Anwendung auf Agriciiltur and Physiologie, 1840. 



^ Recherclies chimiques sur la vegetation. Paris, 1804. 



* Ueber die anorganischen Bestandtheile der Pflanzen. Braunschweig, 1842. 



* Ann. Chem. u. Pharin., 73 (1850), p. 346. 



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