420 Report of Experiments witli different Manures 
undissolved after the application of such solvents as are supposed 
to remove all the other vegetable compounds — namely, the nitro- 
genous substance, the fatty matter, the starch, the sugar, the gum, 
the extractive matters, &c. The substance so remaining general! v 
retains, however, a certain amount of mineral matter, the quan- 
tity of which is determined by the incineration of the fibre. 
The attainment of certain results in regard to the amount of this 
so-called " woody-fibre " is, however, in practice, not a very easy 
matter. It is seldom that two experimenters have adopted the 
same methods for its quantitative estimation. And, although 
it is comparativelv easy to determine whether or not the product 
of the process still retains some of the other matters enumerated 
above, it is by no means so easy to settle whether or not anv 
portion of the substance which it is intended to include under 
the term Woody-fibre, has itself been rendered soluble and re- 
moved. For the results we have to lay before the reader under 
this head, as well as for those relating to the Fatty matter, to 
■which we shall refer further on, we are indebted to Mr. Thomas 
Segelcke, of Copenhagen, who kindly undertook this part of the 
investigation whilst staying in the Rothamsted laboratory. 
It would be out of place to go elaborately into the question 
of method here ; and it is the less necessary as Mr, Segelcke 
will probably publish in detail on this point elsewhere. It may 
be mentioned, however, that he in vain tried to get results which 
corresponded with one another when using the different methods 
that have been recommended. In fact, constancy of result seemed 
to be only attainable, when solvents of a constant strength were 
emploved, for a fixed period of time, and at a given temperature. 
The necessity for observing fixed time and temperature, has been 
insisted upon by Millon ; and the strength of solvents which 
Mr. Segelcke adopted in the analysis of the hays, as giving 
pretty uniform results, was very much the same as recommended 
by M. Peligot. 
The method by which the results given in the Table were 
obtained, was briefly as follows. About "10 grammes of the 
finely ground hay were first fully dried at a temperature of 
212° F. The substance was next digested for three-quarters of 
an hour at a temperature, as nearly as it could be maintained, 
of 180° F., in 150 septems* of sulphuric acid, composed of one- 
part, by volume, oil of vitriol, and two parts, by volume, water.t 
* A septem measure is that of TniTs'h of ^ pound avoirdupois, or 7 grains, of water. 
+ The above is the strength of acid recommended by M. Peligot. In subse- 
quent investigation Mr. Segelcke has found, that results of which the duplicates 
were much more closely agreeing, and which still ranged very close to those 
recorded in the Table and obtained by the method described in the te.xt, could W 
insured by using a weaker acid, but at a higher temperature. So far as his expe- 
riments have yet proceeded, the strength of acid which he has found to be the 
