and Observations on the component Parts of Membrane. 33 1 



was left, which retained the original shape. Pure ammoniac 

 did not disturb the transparency of this solution ; but a copious 

 precipitate of carbonate of lime was obtained, by the addition of 

 carbonate of ammoniac. 



These experiments, on only a few of the Madrepores, suffi- 

 ciently prove how similar they are, in composition, to shell ; for 

 both consist of the same materials, subject to the like modifi- 

 cations. 



Millepora ccerulea. 



This produced much effervescence, when immersed in very 

 dilute nitric acid. The blue colour disappeared, as the calca- 

 reous part was dissolved, and was not afterwards restored by 

 ammoniac. 



Some loose detached portions of a gelatinous substance 

 floated in the solution, which were separated by a filter. The 

 transparency of the solution was not disturbed by pure ammo- 

 niac; but a copious precipitate of carbonate of lime was produced 

 by carbonate of potash. 



Millepora oleic ornis. 



This Millepore, when treated with very dilute nitric acid,, 

 produced a great effervescence ; and, after a few hours, a tender 

 gelatinous substance remained,, which did not retain the figure 

 of the Millepore. 



Pure ammoniac had not any effect; but carbonate of ammoniac 

 precipitated a large quantity of carbonate of lime. 



Millepora polymorpha. 

 This produced an effervescence, when put into dilute nitric 



