S68 Mr. E. N. Horsford on the Value 



tions of copper reduced in the progress of combustion, and 

 secured the most satisfactory results. 



Difficulty presented itself also in the combustion of the beets 

 and other roots, arising from the extreme compactness of the 

 substance when dried. It was however overcome by the me- 

 thod already mentioned. 



The per-centage of woody fibre was determined in the fol- 

 lowing manner. Grains, such as had been analysed, were 

 digested upon a sand-bath, several weeks, in diluted hydro- 

 chloric acid, — one part of acid to a thousand of water. At 

 intervals of from eight to ten days the fluid was poured off', 

 and the digestion resumed with diluted acid, as before. After 

 several weeks, the woody fibre not appearing wholly freed 

 from other substances, an equally dilute solution of caustic 

 potassa was employed, and the digestion therewith continued. 

 At the end of two months, the woody fibre of the oats, barley 

 and buckwheat, were poured upon filters, thoroughly washed 

 with distilled water, and dried at 100° C. The hulls of the 

 peas and beans were treated with diluted caustic potassa alone, 

 and similarly determined. 



To express in 100 parts the results of analyses, the car- 

 bon, hydrogen, oxygen and sulphur of the nitrogenous in- 

 gredients were estimated from the per-centage of nitrogen *. 

 The carbon and hydrogen so estimated, deducted from the 

 whole per-centage of carbon and hydrogen, gave what belonged 

 to the starch, gum, sugar, &c. The oxygen of the latter was 

 estimated from the carbon by the formula C 12 H 10 O 10 f. 



* Mulder's analysis of coagulated albumen, Scheerer and Jones's analyses 

 of legumine and gluten {Ann. de Ch. tend Pharm. xxxix. 360), and Heldt's 

 analysis of the gluten of rye {Ann. de Ch. und Pharm. xlv. 198), differ so 

 little from each other, that a single formula has been constructed upon 

 Mulder's analysis of coagulated albumen, and, with a little modification, 

 employed in determining the elements of the nitrogenous ingredients of all 

 the substances analysed. His per-centage of oxygen was reduced by the 

 per-centage of sulphur, which, according to Dr. Ruling {Ann. de Ch. und 

 Pharm. lviii. 3 Heft.), for gluten = 1*14 per cent, and for legumine 050 per 

 cent. The phosphorus has been neglected, as no accurate determinations 

 of the per-centage of this element has been made. Mucine, discovered 

 by Berzelius, is included in the estimate for the nitrogenous ingredients, 

 since analyses of albumen and of gluten, with and without mucine, corre- 

 spond with each other. 



t The following list of the principal organic bodies containing no nitro- 

 gen, and present in the substances analysed, and their adjoined constitu- 

 tion, will justify the method of calculation : — 



Amylum "| 



Dextrine I r H <-> 



Gum r^ia"ioUio- 



Woody fibre (Payen) J 



Cane-sugar C l2 H n O n . 



