414 J. D. Dana on some modern Calcareous Rock-formations. 
dead coral. The proportion between the living part of a Porites 
one foot in diameter and the dead portion is about as 1 to 50, and 
of the living part, a very large proportion is calcareous, and 
much of the rest is water and the liquids of the body. 
But we may proceed and enquire whether the animal matter if 
present would accomplish the result demanded of it. 
In the first place, 20 per cent. of animal matter contains but 
and’if the sulphur of the sulphate of lime present be added, the 
whole is only 0°5 p. c., or taking the: mean of Prof. Horsford’s 
determination, 0-4 p.c. The amount therefore is not as large as 
would appear from the statement at the bottom of page 250; 
which should be, for 100 parts of the coral material, 
Organic matter, > . ou 
Sulphur, . : ; : o OF 04 
In Prof. Horsford’s second column, 2:05 is not the amount found 
with 20 per cent. of organic matter, but with 100 per cent., and 
hence the discrepancy. Here then, taking the most favorable 
case, and supposing the animal matter one-fifth the whole material 
of the mud, the sulphur that can be counted upon is only four- 
tenths of one per cent. 
In the second place, the transformations supposed in the new 
theory are not possible even if there were ten times the amount 
of sulphur present. gut before considering the “easy explana- 
tion,” we may examine the chemical processes by which it 1s 
supposed to be sustained. 
of the seven ingredients contained, no two were estimated out of 
the same portion. This method, however satisfactory for homo- 
are expressed in percents. In the first place there are 43-99 an 
45-51 for the minimum and maximum of volatile matter, as ascet- 
tained by prolonged ignition of the material—which volatile matter 
includes the sum of the water, organic matter and carbonic acid. 
Now adding up the amount of carbonic acid, water and organi¢ 
matter which follow, as obtained by the special trials, we find 
sng eee 
- ® This volume, p. 250, where he makes the amount of sulphur in 100 parts of 
organic matter 145 p. c. 
