CRYPTOGAMIA. a 
The Equisetacee are remarkable chiefly for containing — 
_ under the cuticle a considerable quantity of siliceous earth. 
“The Eguisetum hyemale contains more silex beneath its de- 
licate epidermis than any other, and is, consequently, most 
employed in polishing hard wood, ivory, and even brass. The 
silex is so abundant, that the vegetable matter may be de- — 
stroyed, and the form retained, as was done by Mr. Sivright.” 
—Greville. é ; oe 
__ The Equisetum hyemale is largely imported from Holland, — 
_ for the purpose of polishing ivory, brass, &c. under the name 
_ of Dutch Rushes. : s 
