On the Identify of Silex and Oxrjgen. IG5 



epidermis and other external parts ; and, hence it is that, in 

 the common experiment of burning a piece ot" charcoal in 

 oxygen gas, the scintillating appearance will be more bril- 

 liant if the charcoal be selected with the lark attached to it. 

 I am assured by a friend, who resided for some years in 

 India, that, in this experiment, he never succt-cded so well 

 as with the charcoal procured fron) the bamboo, and that 

 this produced always a most splendid combustion. Now, 

 the bamboo is known to abound with silex, for, according 

 to Mr. Macie's experiments, the white malier, found between 

 each knot of this reed, proved to be true silex*. In fact, 

 the whole tribe (arunun), and also the straw of oats, wheat, 

 barley, and, perhaps, every vegetable similarly constructed, 

 seem to derive their necessary strength, tenacity, and some 

 other peculiar requisites chiefly from the silex; 



Straw has been very successfully used in this coitntry for 

 the manufacture of paper, and though the colf)ur of this 

 paper remained unchanged, yet in its texture and other pe- 

 culiar properties, it appeared to be little inferior to that which 

 is generally made. The bamboo, T am infonned, answers 

 likewise for this purpose, a?id in some parts of India it is in 

 constant use. This circumstance is an additional proof of the 

 efficacy of silex in the manufacture of paper. I do not recollect 

 that common flax, of which the best paper is principally njade 

 in this country, has yet been analys^ed ; by analogy one 

 would conclude this also must contain tlie siliceous princi- 

 ple. In Mr. Davy's experimentsf, the straw or stems of 

 corn, grasses, and some other vegetables yielded a notable 

 quantity of silex, and, what must be considered as one of its 

 most intimate associates, there was also carbonate of potash ; 

 and from the ashes of straw, a piece of line white transparent 

 glass was produced, perfectly soluble m water and indecom- 

 posable by acids, The'culn)S of the grasses ivppeared to Mr. 

 D. to contain more silex and a much larger proportion of 

 potash even than tlic corn. In 200 grams oi the culm of 

 wheat, which, «heni)urned, gave 31 of ashes, this oenlle- 

 jnan obtained ]3 grains of silex and 1 8 oj-' potash, which waa 



• Pldlot. Traits. July, 1791. f i'hUot. Journ. May, J799. 



li 3 probably 



