SCIENTIFIC NEWS. 311 



been raised to its present elevation from.the bottom of the deep 

 sea by which it is now surrounded. 



Incombustible Ctoik. 



It appears, that the ancients had a method of making incom- 

 bustible cloth of amianthus, which, notwithstanding the flexi- 

 bility of its fibres has generally been considered as too brittle to 

 be worked without a mixture of some other staple, such as 

 flax, or cotton, to be afterwards burned out. Madame Perpentl 

 has succeeded in working it with facility alone, after several 

 trials from the writings of ancient authors. 



Much depends, of course, upon the quality of the article 

 itself. Her process consists, in softening the amianthus in 

 water*, beating it, rubbing it, and dividing with a double comb, 

 with fine steel points. It is remarkable, that the fibres thus 

 obtained are much longer than the solid piece, and may be had 

 of the most extreme delicacy for fine fabrics. They are said to 

 be as strong as those of silk or linen. - 



She has manufactured paper of this material, making use of 

 gum to give consistence to the pulp. If an incombustible ink 

 be required, the oxide of manganese wouid present itself as a 

 preferable ingredient. 



To Mr. Nicholson, 



Sir, 



Your correspondent O, in No. 158, will oblige a constant 

 reader of your Journal to remove the follow ing ambiguities in 

 the extraction of the square and cube roots : 



Sir, 

 Your obedient Servant, 



B. 

 If 



