58 Si lex in Vegetables, 



the mineral acids. Ten grains of this was fufed with 34 grains of potafli. The compound 

 was foluble in water. The nitrous phofacid threw down from the aqueous folution a white 

 flocculent matter, which was neceflarily flint ; this matter I did not weigh, but I conjcdlure 

 that it was about feveii or eight grains. One hundred and ten grains of the reed from whence 

 the epidermis was removed, gave about fix grains of flint. 



,D. 8. I now examined the culm of wheat: 200 grains, burnt, gave 31 grains of white 

 aflies ; of thefe 18 grains were foluble, with efFervefcence, in the muriatic acid. The re- 

 mainder had all the properties of filex. The matter difTolved in the muriatic acid was pot- 

 afli. The aflies of oats and barley afforded filex in nearly the fame quantities as thofe of 

 wheat. The culms of the grafles, among which I examined anthoxanthum, poa pratenlis, 

 and fome others, appeared to contain more filex in the epidermis, than even the corns with a 

 much larger proportion of carbonate of potafli. 



D. 9. The filex in all thefs vegetables, as in the canes, appeared to be contained in the epi- 

 demis, or in the fecond bark. When the plants are carefully burnt, the figure of the 

 epidermis is preferved. In the cane, when well burnt, it has a white glofly appearance,, and is 

 femi-tranfparent. In the reeds, corns, and grafles, it is white and opaque, and when viewed 

 through a magnifier, appears to confifl: of longitudinal threads joined together by net work. 

 In the microfcope, even the fmallefl: particles have a diftinA reticular appearance. 



D. 10. The quantity of carbonate of potafli in the aflies of the corns and grafles, in- 

 duced me to fuppofe that, in a fl:rong heat, they might be fufed into glafs. The aflies of the 

 arundo phragmites were expofed to the flrongefl: heat of an air-furnace for fome minutes ; 

 there was no appearance of fufion ; the carbonate of potafli was not fufKcient to form glafs 

 with the filiceous earth. The afliies of ftraw, in a flrong heat, gave a fine white tranfparent 

 glafs, perfeftly infoluble in water, and indecompofable by acids. The aflies of hay gave a 

 black glafs, with a fuperabundance of potafli. This converfion of corn and grafs into glafs, 

 may be effefted by the blow-pipe, and affords a pleafing experiment. A fl:raw burnt with 

 the blow-pipe, and urged with the ftrong heat of the blue flame, beginning at the top, is con- 

 verted into a fine pellucid globule of glafs almofl: fit for microfcopic experiments. A culm of 

 grafs is fufed under the blow-pipe into a globule of glafs, black and opaque, probably from its. 

 containing iron. 



D. II. Thefe fafts will afford fome curious inferences to the fpeculator on organized 

 nature. The flint entering into the compofition of thefe hollow vegetables, may be confidered 

 as analogous to the bones of animals ; it gives to them ftability and form, and by being fituated 

 in the epidermis, more effeftually preferves their veffels from external injury. They will pro- 

 bably enable us to determine whether filex be a Ample or a compound fubftancc. Reed or 

 wheat mi"-ht be eafily made to vegetate deprived of filex. Confined under mercury, in a foil 

 compofed of known quantities of the feline earths, and fuppliedwith diftilled water and fafli- 

 tious air, we might difcover whether It would compofe filex, or fubftitute for it another earth. 

 This experiment, as well as fome others on the fame fubjeft, we propofe to make, if leifure 

 aiKl opportunity occur. The numerous complex attra<5lions of organic beings, refulting from 



their 



