fame chemical Experiments on Tabalheer. 387 
4. The alhes, obtained by burning the bamboo, boiled in 
marine acid, left a -very large quantity of a whitilh infoluble 
powder, which, fufed at the blow-pipe with foda, effervefced, 
' and formed a tranfparent glafs. Only the middle part of the 
joints was burned, the knots were fawed off, left, being po- 
rous, Tabalheer might be mechanically lodged in them. How- 
ever, the great quantity of this remaining fubftance fhews it 
to be an effential, conftituent part of the wood. 
The a flies of common charcoal, digefted in marine acid, left 
in the fame manner an infoluble refiduum which fufed with 
foda with effervefcence, and formed glafs ; but the proportion 
of this matter to the allies was greatly lefs than in the foregoing 
cafe. 
5. Since the above experiments were made, a Angular 
circumftance has prefented itfelf. A green bamboo, cut in the 
hot-houfe of Dr. Pitcairn, at Iffington, was judged to con- 
tain Tabalheer in one of its joints, from a rattling noife dif- 
coverable on lhaking it; but being fplit by Sir Joseph Banks, 
it was found to contain, not ordinary Tabalheer, but a folid 
pebble, about the fize of half a pea. 
Externally this pebble was of an irregular rounded form, of 
a dark-brown or black colour. Internally it was reddilh-brown, 
of a clofe dull texture, much like fome martial filiceous ftones. 
In one corner there were fliining particles, which appeared to 
be cryftals, but too minute to be diftinguilhed even with the 
microfcope. 
This fubftance was fo hard as to Cut glafs ! 
A fragment of itexpofed to the blow-pipe on the charcoal did 
not grow white, contract in lize, melt, or undergo any 
change. Put into borax it did not diflolve, but loft its colour, 
E e e 2 
