892 Transactions of the American Institute. 



been driven into the sand, the weight of hammer used, the number of blows, the 

 fall of the hammer, and the last blow given, and the amount of the settlement of 

 the pile by the last blow. 



You will also have six of the piles, which were first driven, drawn up, provided 

 they can be drawn up by the application of a power not exceeding ten tons, care- 

 fully noting the amount of power required to draw the piles in each case. If the 

 application of a power equal to ten tons to each of the six piles will not draw them, 

 then let one pile be drawn to ascertain how much power is required for the purpose. 



The result of these experiments will enable the Bureau to judge whether the 

 foundation is of the most solid construction, according to the nature of the soil, 

 and intention of the contract. 



Respectfully, 



Your obedient servant, 

 (Signed.) JOSEPH SMITH. 



Capt. Jno. Thos. Newton, Commanding A*avj/ Yard, Pensacola. 



As I had the pleasure of assisting at these experiments, I am 

 able to present the following facts, which were carefully noted at 

 the time: 



The material into which all the piles were driven was sand, clean, 

 sharp, homogeneous, granulated silica, quite free from dirt or any 

 kind of pasty material. 



There was no rubbish, vegetable deposits, pebbles or stones of 

 any kind, and all the sand would pass through a sieve, having open 

 ings one-twelfth of an inch square. 



The piles were of yellow pine, thirty feet long, averaging thirteen 

 inches diameter at the middle of their length, round, and driven 

 with the bark on. 



The points were sharpened to the form of a square pjTamid, two 

 feet to two and a half feet in length. 



Every pile was banded with a hoop of best bar iron, three by 

 one inch in section, and driven in all cases without a follower. 



The average weight of the piles was 1,500 to 1,700 pounds. 



The piles were driven four feet apart in water about eleven and 

 a half feet deep. 



Average depth into compact sand, fifteen feet. 



Average number of blows given each pile, with a ram weighing 

 4,087 pounds, was sixty-nine. 



Average ditto, with a ram weighing 4,478 pounds, was sixty- 

 four. 



The ram falling thirty-three feet the last blow, and all the blows 

 given at the rate of two and a half per minute. 



Long experience in driving piles in the compact sand of Pensa- 

 cola harbor, showed that the limit of endurance of a yellow-pine 



