of certain Soils and Waters hi Belgium. 37 



any positive relation between the composition of the plant and 

 the composition of the soil upon which it grows. To answer 

 these questions even approximatively, will require investiga- 

 tions frequently repeated, and the concurrent labours of many 

 different investigators ; and although my present inquiries may 

 serve to furnish certain grounds for arriving at an opinion upon 

 these points, I would not in any way be understood as putting 

 them forward with that view. 



My main object, in the inquiry which forms the subject of 

 the present paper, was to ascertain, if possible, whether there 

 existed any difference between the composition of the ashes of 

 the ordinary flax of Ireland and the flax grown in those loca- 

 lities in Belgium, where that plant is known to yield a fibre of 

 so much commercial value. Further, to ascertain the compo- 

 sition of the soils of those districts, in order to compare them 

 with the soils of the localities in Ireland where flax is, or may 

 be, successfully cultivated. Finally, as it is known that in the 

 preparation of the fibre the most important stage consists in 

 the steeping or retting of the plant, I considered it of the 

 greatest interest to trace, if possible, whether the superior qua- 

 lities of some rivers or ponds in Belgium could be connected 

 with any peculiarity of chemical constitution. For the mate- 

 rials and specimens necessary for these investigations, I am 

 indebted to the kindness and liberality of Mr. Marshall of 

 Leeds ; who was anxious also to connect therewith the dis- 

 cussion of some most important points of special technical 

 application, for which, however, the pressure of other avoca- 

 tions did not allow me time. I therefore publish the results 

 contained in the present paper, solely under their scientific 

 relations to agricultural chemistry and physiology, and shall 

 not enter upon any considerations belonging to manufacturing 

 practice. 



Before entering into the description of the numerical re- 

 sults of the analyses, I think it better to premise a succinct 

 notice of the modes of analyses adopted for the different classes 

 of substances, as I shall thereby be enabled to avoid a great 

 deal of repetition. 



I. Of the Modes of Analyses used for the Ashes, Soils and. 

 Waters. 



The preparation of the flax-ashes was effected by chopping 

 up the plant stems into moderately small bits, and then car- 

 bonizing them gently in a Hessian crucible. The material so 

 obtained was further incinerated by very gentle ignition in a 

 platinum capsule over a gas flame; but it. was not in any way 

 sought to burn off all charcoal, or to obtain the ash perfectly 



