TIMBER USED IN CONTACT WITH BOIL. 47 



difficult to split as possible. For this reason, in order to preserve 

 to the full the strength of the log, it should be used quite round. 

 A round section also makes the work of driving the piles easier. 

 If deep water constantly stands over the piles, less durable woods 

 especially such as last well under water, and at the same possess 

 the other requisite qualities, may be used. Trees which grow up 

 with a long straight, clean bole furnish the best piles. Where s41 

 grows it is the best wood for the purpose. Terminalia belerica 

 has been used under the Mortakka bridge where the Rajputana- 

 Malwa Railway crosses the Narbada. 



2. For strengthening roadways and stream banks. 



In numerous towns in England and America and also in Paris, 

 some of the streets have been paved with short blocks of wood 

 laid, with the fibres standing vertically, on concrete, such roadways 

 deadening the noise of traffic and being less trying for horses than 

 those formed of asphalte or stone pavement, and more durable, 

 less dusty and more easily repaired than a macadamised surface. 

 Woods used for this purpose must be hard and tough, besides 

 being as durable as possible. 



On unmetalled roads many portions, from excess of moisture, re- 

 main soft during the whole year, or at least for many months after 

 the rains. Such portions are made easy for traffic by laying wood 

 across the roadway. Wood so used is subject to the unchecked 

 action of every influence of decay, and hence unless they can be 

 renewed every year, only durable pieces should be used to form the 

 foundation of the way, only the small branch wood laid on the 

 surface requiring to be put on afresh every year or even oftener 

 according to the volume and constancy of the traffic. 



Lastly, stream banks have often to be protected against erosion 

 by forcing the current away by means of spurs formed of wooden 

 crates filled with stones. The crates being always roughly made, 

 are constructed of only round wood, which should, however, be 

 very durable and, if possible, consist exclusively of heartwood. Sd.1, 

 kbair Hardwickia hinata, and other similarly hard and durable 

 woods are the best for the purpose. 



3. Railioay sleepers. 



The total mileage of railways in India in February 1890 was, 

 in round numbers, 14,200 miles, requiring, with double lines, 

 sidings, &c., about 32,000,000 sleepers for original construction, and 

 about 3,000,000 annually for maintenance, supposing the way to 

 have been laid only with wood. To meet so enormous a demand has 



