THE VOLATILE PAET OP PLANTS. 61 



Bye-straw fiber. Linen fiber. 



Water 8.65 5.40 



Ash ...2.05 .1.14 



N 0.15 0.20 



C 42.47 38.36 



H 6.04 5.89 



O... ...40.64 48.95 



100.00 100.00 



On deducting water and ash, and making proper correction for the 

 nitrogen, the above samples, together with one of wheat-straw fiber, 

 analyzed by Henneberg, exhibit the following composition, compared 

 with pure cellulose. 



100.0 100.0 100.0 100.0 



Franz Schulze, of Rostock, proposed in 1857 another method for esti- 

 mating cellulose, which has recently, (1866,) been shown to be more cor- 

 rect than the one already described. Kuhn, Aronstein, and H. Schulze, 

 (Henncbeirf s Journal fur Landwirtlischaft, 1866, pp. 289 to 297,) have ap- 

 plied this method in the following manner : One part of the dry pulver- 

 ized substance, (2 to 4 grams,) which has been previously extracted with 

 water, alcohol, and ether, is placed in a glass-stoppered bottle, with 0.8 

 part of chlorate of potash and 12 parts of nitric acid of specific gravity 

 1.10, and digested at a temperature not exceeding 65 F. for 14 days. At 

 the expiration of this time, the contents of the bottle are mixed with 

 some water, brought upon a filter, and washed, firstly, with cold and 

 afterwards, Avith hot water. When all the acid and soluble matters have 

 been washed out, the contents of the filter are emptied into a beaker, 

 and heated to 165 F. for about 45 minutes with weak ammonia, (1 part 

 commercial ammonia to 50 parts of water) ; the substance is then brought 

 upon a weighed filter, and washed, first, with dilute ammonia, as long as 

 this passes off colored, then with cold and hot water, then with alcohol, 

 and, finally, with ether. The substance remaining contains a small 

 quantity of ash and nitrogen, for which corrections must be made. The 

 liber is, however, purer than that procured by the other method, and a 

 somewhat larger quantity, (^ to 1)^ per cent,} is obtained. The results 

 appear to vary but about omper cent from the truth. 



The average proportions of cellulose found in various vegetable 

 matters in the usual or air-dry state, are as follows : 



