136 HARBOUR CONSTRUCTION. 



square and 40 feet in length. It is fairly strong, and is easily 

 worked. After creosoting, the surface of the timber should be 

 disturbed as little as possible, because it contains by far the 

 largest share of the creosote. 



Where practicable, all notching and cutting should be done 

 before the timber is creosoted. When this cannot be done, the 

 newly exposed surfaces should be well served with hot creosote, 

 and the joints should be made as close as possible. 



I have seen creosoted half-logs halved after creosoting 

 used as bracings and walings, destroyed by the worm just as 

 quickly as if they had not been creosoted at all. 



Pitch Pine and Oregon Pine are valuable chiefly on account of 

 the great length and large scantling of the logs, or masts, which 

 can be obtained. They are generally employed in the construc- 

 tion of staging, and are excellent, strong timbers ; but they are 

 quickly attacked by sea-worms. Staging in which they are 

 used ought, therefore, to be carefully examined periodically. 



Oak and Teak are good timbers for pile-work, and for many 

 other purposes. They are not so freely attacked by the worm 

 as those of the pine family, and in many situations they are 

 very durable. They may be obtained, without difficulty, in logs 

 of from 12 inches to 20 inches square, and from 20 feet to 35 

 feet in length. English oak is, however, becoming scarce. 



Greenheart is the wood, of all others, upon which engineers 

 rely for durability in sea-works, Although it sometimes fails 

 as has already been pointed out it is generally proof against 

 sea-worms of all kinds, and in exceptional localities where 

 greenheart will not stand, no other timber will. 



It is very strong and tough, but piles are liable to split when 

 being driven. They should, therefore, be afforded temporary 

 support during this operation, by bolting on strong iron bands 

 or cramps, not only near the head, but also at intervals of say 

 6 or 8 feet throughout their length, as circumstances may 

 indicate. It is much easier to prevent a split than to stop one 

 when once started. 



The usual immunity enjoyed by greenheart from the attacks 

 of sea-worms is due to the poisonous oil which it contains. A 

 wound caused by a splinter of this wood almost invariably 

 festers. 



Logs from 12 inches to 15 inches square, and up to 40 feet in 

 length, may be easily obtained. 



