TOL. XC.] PHILOSOPHICAL TRANSACTIONS. 715 



which possessed all the characters of Chaptal's animal soap. When the stem of 

 this gorgonia was exposed to a red heat in a retort, or crucible, it curled up, and 

 smelled like burnt horn ; after which, a spongy coal remained, of difficult inci- 

 neration. By a long continuation of the heat, a residuum was left, so small as 

 scarcely to be collected, which, being dissolved in dilute nitric acid, afforded, by 

 the addition of ammonia, a slight precipitate of phosphate of lime. Another 

 species of gorgonia, which much resembled the suberosa, excepting that the 

 cortical part was much larger in proportion to the stem, was next subjected to 

 examination, and proved to be of a similar composition with those already mentioned. 



Gorgonia pectinata. — The cortical part of this gorgonia effervesced with dilute 

 nitric acid, and left a soft yellowish white membrane. Ammonia precipitated a 

 small quantity of phosphate of lime ; after which a copious precipitate of carbo- 

 nate of lime was obtained by potash. The stem, in its habits, resembled those 

 which have been described. 



Gorgonia setosa. — An effervescence was produced on the immersion of this 

 gorgonia in dilute nitric acid ; and after some hours the cortical part appeared like 

 a thin yellowish membrane, which coated the horny stem. The acid solution, on 

 the addition of ammonia, yielded a slight precipitate of phosphate of lime ; and 

 a large quantity of carbonate of lime was afterwards obtained by potash. When 

 the cortex was separately steeped in the acid, and the solution examined in the 

 way so often mentioned, only carbonate of lime was obtained*. On the contrary, 

 the stem, whether recent or burnt, afforded a small portion of phosphate of lime, 

 but scarcely any trace of carbonate. The stem which had been long steeped in 

 the acid, became soft and transparent, like a cartilaginous or tendinous substance. 



The gorgoniae which have been enumerated, much resemble each other in the 

 composition of their cortices, as well as in the nature of their stems. In the 

 cortex, the predominant hardening substance is carbonate of lime ; but in the 

 stem phosphate of lime is the chief and almost the only earthy substance that is 

 present. 



The following gorgoniae, though in like manner invested by a cortex, are 

 different, as they do not afford any phosphate of lime. Gorgonia umbraculum, 

 g. verrucosa, and 3 other species not described, so much resemble each other in 

 their chemical characters, that it would be superfluous to give a separate account 

 of them. The cortical parts of these gorgoniae were separately immersed in dilute 

 nitric acid. An effervescence immediately took place, and after some time they 

 were found in the state of soft pulpy yellowish white membranaceous bodies, 

 retaining nearly their original size and form. The acid solutions did not afford 

 any phosphate of lime when ammonia was added ; but a large portion of carbonate 

 of lime was precipitated by solution of potash. The stems of these gorgoniae, 



* When the cortical part had been long digested in boiling distilled water, a brownish solution was 

 formed, which was but little affected by infusion of oak bark ; but nitro-muriate of tin produced a 

 precipitate — Orig. 



4 Y2 



