[97 ] 
ends of the branches it is not fo hard *s the bark; in 
fome places near the ends it is of equal hardnefs 
with it ; but in the thick branches and trunk it is 
harder. 
§ 10. This fubftance, being obferved by a mi~ 
crofcope, in corals of one colour, as the red, and 
thofe which are not corroded by worms, appears 
uniform, fmooth, without fpots of other colours, 
without holes or pits, but quite even, hard, and ca- 
pable of a perfect polifh. 
§11. But it is otherwife, in corals of more colours 
than one ; as, fometimes, in thofe of a yellowifh 
rofe -colour, and thofe of a rofe-colour. For I have 
fome branches of thefe, the tranfverfe fedtions of 
which exhibit different lines, or annular bands (Fig. 
D. s, s, s, s,) whereof one part is a rofe-colour, and 
the other yellowifh, others white, and others more 
or lefs charged with colour, which form concentric 
circles, D. a, like the coats of an onion. 
§12. The fame fort of annular lines is obfervable 
in red coral a little burnt, but they are of a grey co- 
lour, and parted afunder by a line of a deep-brown 
grey (j, s, Fig. D.). 
§ 13. When this fubftance, tho’ very hard, hap- 
pens to be ftripped of its bark, either by age, or fome 
other accident, it is liable to a fort of teredo , or worm ; 
which is a fmall animal, that enters into the body of 
the coral by very fmall holes, (Fig. C, #, a,) gnaws 
its infide, and makes itfelf roundifh cells therein, 
(C. j, j,). Thefe cells have a communication with 
each other, (C. a, a,) and are feparated by very thin 
partitions, which weakens the coral extremely, and 
makes it brittle and improper for any fort of work. 
N § 14. 
