APPENDIX. 129 
afford sufficient precipitate for analysis. The carbonate of lime, by far the most abun- 
dant constituent, was separately determined on one gramme, as sulphate of lime, and 
from this the carbonate was calculated. The ratio of phosphates and fluorides of the 
several bases to the entire mass, was also determined from a distinct portion of coral, two 
grammes by weight; and from the data thus furnished, we have the means of safely 
estimating the organic matter by the loss. 
“Organic Mutter.—This constituent of the corals deserves particular notice. Some 
remarks have already been made on it, when speaking of the colouring matter of corals. 
This organic matter is so intimately united, throughout the whole structure of the corals, 
amounting to 4-8 per cent., that it cannot be separated by any method resorted to, ex- 
cept by repeated deflagrations with the nitrate of ammonia. When reduced to the finest 
impalpable powder, it may be digested in repeated doses of boiling water, until no trace of 
organic matter is longer found in the water, and yet a careful analysis, by falling short 
of the amount required to complete the 100 parts, will invariably show its presence. 
The oxalate of lime obtained in their analysis, if ignited (as in the usual manner directed 
for the estimation of lime), will always have a dark carbonaceous hue, derived from the 
organic matter of the coral. 
“ During the solution of considerable quantities of several corals, whose analyses are 
given beyond (particularly in No. IV., but more or less in all), a large quantity of 
fatty (!) matter separated, of a yellow colour and disagreeable penetrating odour, though 
not fetid. It was easily seen floating on the surface of the solution, in transparent jelly-like 
masses of a yellowish colour. It was insoluble in aleohol, but readily so in cold ether, 
and the evaporation of its etherial solution yielded a yellow solid, resembling wax. It 
fuses below 200° F. A pungent irritating odour arose from the evaporation of the etherial 
solution near its close, which acted powerfully on the eyes and nostrils. This volatile 
principle may be analogous to that known to proceed from the decomposition of fat 
(acrolein?). It deserves more attention than I have been able to give it, particularly as 
it may perhaps be the source of the disagreeable odour of some limestones of coral 
origin. 
“« Analyses.—The following tables exhibit a comprehensive view of the results of the 
several analyses. The relative proportions of organic matter, carbonate of lime, and the 
complex precipitate of phosphates and fluorides thrown down by lime-water, are first 
given; and afterwards the definite composition of this precipitate in the nine species more 
minutely investigated. 
Porites. Porites. Porites. Porites. Porites. 
No. 1 (1.) No. 3. No. 4. No. 5. No. 6. 
Carbonate of lime, 95-84 94-412 94-807 93-875 389-864 
Phosphates and fluorides, 2-05 0-900 0-950 1-561 0-700 
Organic matter, 2-11 4-688 4.243 4-564 9-431 
Porites. Porites. Madrepora. Madrepora. Madrepora. 
No. 7. No. 8. No. 9 (II.) No. 10 (III.) No. 11 dV.) 
Carbonate of lime, 94-438 95-000 94-807 92-815 95-086 
Phosphates and fluorides, 2-100 1-650 0-745 0-600 0-300 
Organic matter, 3-462 3-350 4-448 6-585 4-614 
33 
