of Edinburgh, Session 1872-73. 
183 
special object of the notice was, however, to show that timber sub- 
jected to preservative processes did not long resist the attacks of 
the Limnoria, and, more especially, that thoroughly creosoted 
timber is readily perforated by it, and subsequent experience has 
fully shown that these statements were correct. 
In that notice I also said that the timber known as G-reenheart 
has the valuable property of resisting the attack of the Limnoria, 
a statement which occurs in many works on Engineering and 
Botany, and has hitherto been universally believed to be correct. 
Recent experience, however, has satisfied me that this conclusion, 
if not absolutely incorrect, requires considerable qualification, and 
the object of the present notice is to communicate some facts 
which have been ascertained since the date of my former notice to 
the Society. 
The Bebeeru or G-reenheart tree, as is well known, is a native of 
British Guiana belonging to the order Lauraeem, and its bark pro- 
duces sulphate of bebeerine, which is used medicinally as a tonic. 
The colour of the timber, as imported and used in engineering 
works, is generally light olive-green (hence its English name), with 
occasional darker shades approaching to brown. It can readily be 
got in logs of from 40 to 50 feet in length, and 10 or 15 inches 
square. The timber, as sent to this country, has very rarely any 
sap wood; the logs are seldom straight grown; and the wood, which 
is hard and close grained, is extremely difficult to dress owing to 
its tendency to split when cut up into deals or slabs. Its specific 
gravity is high ; its weight being about 50 lbs. per cubic foot, 
while that of the best Memel does not exceed 30 lbs. 
Independently of its supposed exemption from the ravages of 
the Limnoria, the fact that the breaking strength of greenheart, as 
compared with Memel, is as 1 to T51, renders it very suitable for 
many engineering works, and particularly for staging in situations 
of great exposure. It was, I believe, for the first time employed for 
staging at Wick Bay, where logs of pine could not withstand the 
waves ; and it was on removing the temporary greenheart staging, 
that had been in use from two to four years at Wick, that I first 
became fully aware that the Limnoria would perforate that timber. 
Some of these logs were found to have been attacked by the Lim- 
noria throughout the whole surface, extending from about low- 
2 A 
VOL. VIII. 
