NOTES ON THE PROPERTIES OF WOOD. 



specific dry weight. Square-cut timbers laid horizontally with their 

 yearly rings have not by far such bearing power as when laid perpen- 

 dicularly. 



Green wood has considerable elasticity. Young steins, although they 

 suffer sometimes by the wind, will regain their original position in a 

 short time. Here it is necessary to mention that where young stems or 

 branches have been bent through snow for a longer period, they will 

 not return to their former form. 



I submit the following as the result of some experiments rela- 

 tive to the bearing capacity of various woods. The pieces were all 3 

 feet long, and 2 inches by 1 inch, and air-dry. The constants arrived at 

 were the following : — 



Yellow Pine 



Constant. 

 . 358-5 



Wet. 



Weight, 

 per C. Ft. 



25-687 lb. 



Baltic Pine 

 Red Pine . 



. 444- 

 . 467- 





29-062 „ 

 33-437 „ 



Ash . 



. 517-75 



53-875 



41-812,, 



English Elm 



. 595-25 . 





37-312 „ 



Pitch Pine 



629- 





45-750 „ 



American Elm 



. 631-5 





45-312 „ 



American Oak 

 African Teak 

 Mora 

 Sabicu 

 African Oak 



653-5 

 . 673-5 

 . 691- 



854-25 . 

 869-5 





44-875 „ 

 60-562 „ 

 71-250 „ 

 59-687 „ 



Greenheart 



1,079-5 





69-750 „ 



English Oak . 



— 





53-312 „ 



Indian Teak 



— 





38-125 „ 



Ironwood 



— . . 





73-500 „ 



English Larch 



— 





32-562 „ 



Formula to find the breaking-weight of a piece of timber : — c 

 constant, b breadth in inches, d depth in inches, I length in feet, w break- 

 ing-weight in pounds. 



c b d* 



I 



The adaptability of greenheart for hydraulic construction, dock- 

 gates, &c, cannot be over-estimated. I may refer to an instance where a 

 clough was taken out of a sewer after sixteen years : it had been made 

 half of oak and the other half of green-heart ; the oak was completely 

 worm-eaten, whilst the green-heart was in its original condition. This 

 certainly contrasts with the fact mentioned by Mr. Burnell in his paper, 

 that he has a piece of green-heart riddled by the teredo ; and it would 

 be interesting to ascertain under what circumstances the teredo 

 will attack or not attack this kind of wood. My experience proves that 



