382 ON THE CONSTRUCTION OF 



Keep a few people for five or six days, rubbing the surface 

 with water, lime and molasses mixed, so long as a crack ap- 

 pears, and afterwards rub the whole over with any common oil. 

 It is difficult to describe this process, but a little experience will 

 point out what is necessary. 



7th. The annexed table of the gravity and strength of wood 

 will inform you. 



Result of experiments made on the weight and strength of timber 



used in Bengal. 



The pieces on which the experiments were made, were each 

 square prisms, twenty-four inches long, and one inch on the 

 side; the distance between the props of support was twenty-two 

 inches, and the weight was suspended from the center of the 

 piece. 



, Weight of Weight suspended 



Names of the wood each piece. when it broke. 



oz. ft " oz. 



/Teak. - - - - 11 - - - - 449 13 



Tissoo. - - - 12.1 - - - - 459 5 



(Saul. - - - - 13 - - - - 535 12i. 



lAssum, like Saul. 132. - - - - 559 9 



5 ( Soondry. - - - 15i, - - - - 593 9 



'Napaul Fir. - - 9| - - - - 389 



Baltic red Fir* 10 - - - - 346 9 



| (Ditto white Firf 7 - - - - 214 13 



* Very dense and full of rosin. -f In general use. 



N. B. A quantity of pure water, of the same bulk with one 

 of the above pieces of wood would weigh 1 3JL ounces. Hence 

 they would all float in water except the Soondry. 



You must not use knotty or curled wood for your beams, 

 and all beams must be rounded or cambered upwards, in the pro- 

 portion of two inches to twenty feet, as the terrace will bring 

 them down a little. 



In a twenty-two feet space, Saul beams, ten byleven or eight 

 inches, are quite sufficient, placed at three feet from centre to 

 centre. 



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