2 HORTUS GRAMINEUS WOBURNENSIS. 



ticular seasons at which the different species attained to the 

 greatest degree of perfection, were attentively observed, as hke- 

 wise the time of flowerino-, and the period of perfecting the seed. 

 Their comparative value, therefore, in regard to produce, and the 

 particular seasons at which it was in perfection, with the kinds of 

 soil most favourable to their growth, and the peculiar habits of 

 the different species, were, by these means, satisfactorily ascer- 

 tained; but the comparative degree of their nutritive powers, (a 

 point of the first importance), was still to be determined. 



Those who have made experiments, to prove the comparative 

 degree of nourishment contained in different species of food, by 

 means of feeding, and weighing, have found the results of such 

 experiments quite inconclusive ; and the impossibility of ever 

 determining by tins process, the absolute degree of nourishment 

 supplied to cattle by any kind of food, almost certain ; for, 



First ; The quality of the same species of food will often vary, 

 from one to twenty per cent, in the course of the experiment. 



Secondly; Different breeds or varieties of animals, acquire va- 

 rious proportions of flesh, from equal quantities of the same 

 species of food consumed by them. Or, 



Lastly; Scarcely two individuals of the same breed can be 

 found, that will gain equal weights of flesh from equal quantities 

 of the same kind of food. With a view to this point only, it would 

 therefore have been a vain labour, to have submitted so sfreat a 

 number of different plants to the experiment of feeding and 

 weighing, and which would require at least to be made on four 

 hundred head of cattle of the same breed. 



His Grace judged that the inquiry would be effectually assisted 

 by the aids of chemistry; and a simple chemical process, recom- 

 mended for this purpose by Sir Humphry Davy, ascertained the 

 important point in question in the most satisfactory manner. 



As this mode of determining the nutritive powers of grasses, by 

 chemical process, is a new path of investigation opened, and 

 such as, on a subject of this consequence, should always be pro- 

 ceeded in with caution at first, it may not be unnecessary to say a 

 few words respecting the accuracy of its results. 



The grass, in a green or dry state, is submitted to the action of 

 hot water, till all its soluble parts are taken up. The liquor is then 

 separated from the woody fibre of the grass by means of blotting 

 paper ; it is then evaporated to dryness. The product or solid 

 matter, is the nutritive matter of the grass. Sir Humphry Davy 



