and Observations on the component Parts of Membrane. 349 



the whole was dissolved, and a very dark coloured animal soap 

 was formed. 



When this Gorgonia was exposed to a red heat, it emitted 

 much smoke, with a smell of burned horn : it soon lost its 

 shape, puffed up, and formed a spongy coal, which, by a long 

 continued heat, left a few particles of a white substance, con- 

 sisting chiefly of muriate of soda. 



Another species of Gorgonia was next examined, the stem of 

 which is from one quarter to nearly half of an inch in diameter 

 in the thickest parts ; of a black colour, and a high polish, like 

 black sealing wax : it has probably been considered as a variety 

 of Gorgonia Antipathes. 



This, by immersion during 28 days in dilute nitric acid, 

 gradually became semi-transparent, and of a bright brownish 

 yellow. In this softened state, it was steeped two days in water, 

 and was then opened longitudinally. By this, the whole struc- 

 ture became apparent, and consisted of thin coats or tubes of a 

 beautiful transparent membrane, which, beginning from a cen- 

 tral point, progressively became larger, according to the order 

 by which they receded from the centre. 



These membranes were so delicate, that the fibrous texture 

 could scarcely be discerned. 



The acid in which this species had been steeped, was tinged 

 with very pale yellow. Ammoniac being added, changed it to a 

 deep yellow or orange colour; but the transparency of the 

 liquor was not disturbed by this, or any of the other precipi- 

 tants which had been employed in the former experiments. 



When this Gorgonia was exposed to a red heat, it crackled, 

 and emitted a thick smoke, with the smell of burned horn. The 

 shape was soon destroyed, and a compact coal remained. 



