38 



Experiments on the Adhesion of Iron Spikes, 



in the seasoned oak the fornaer was 18^ per cent, superior to the 

 latter. It is also apparent that the advantage of seasoned oak over 

 seasoned yellow pine for retaining spikes, is, by a comparison of ex- 

 periments 1 and 3, as 1 to 1.9 ; and by a comparison of 2 and 4, it 

 is as i to 2.37. In the preceding experiments the spikes were 

 driven into the timber and immediately drawn out again. In the 

 second series, the spikes were driven into their I'espective pieces of 

 timber, and then soaked for a few days in water. The pieces into 

 which the different spikes were driven, were as nearly alike as it was 

 practicable to obtain them, being always cut from the same plank, 

 avoiding knots, cracks, he. The following table contains a view of 

 the experiments after soaking the timber. 



TABLE II. 



Timber soaked after the spikes were driven. 



RF.M.4RICS. 



Experiment No. 1. — In this and the four following, the thickness of the spike is 

 that at the bottom of the grooves. 



Expcrimenb No. 4. — The oak used in this experiment was firmer than that em- 

 ployed in the first series. 



Experiment No. 5. — The timber had been slightly split by the driving of this 

 spike. 



Experiment No. 6.— The llanches remained after filing out the swelled part of 

 the original form. 



Experiment No. 12. — Timber slightly .split in driving the spike. 



