63 
weather in general, t he placed into vvbich ( be spikes are driven, whether 
driven more into the heart-wood or into the sap-wood 5 the closeness, 
boo, of the contact with the foot of the rail requires consideration in 
determining the adhesion of the spike for practical purposes. Yet, from 
the average results represented in the seven tables, the following im- 
portant conclusions can be drawn : 
A. For Oak. 
( 1 ) In t ies with good, tough, dense fibers the adhesion was found to be 
greater when holes of ( 7 ( . or even .£ an inch were bored than when this 
was not done. 
(2) In quickly-grown oak ties the reverse was the case, but the dif- 
ference was insignificant (—67.2) ; and as such ties split and check more 
easily, boring of these also must be considered advantageous. 
(3) The friction due to presence of water in the tie (influence of the 
weather) exerts greater resistance to displacement than the friction of 
the spikes against the rails. 
(4) In a f-inch hole the average adhesion was slightly less than when 
the ties were not bored ( — 24). 
(5) Only in holes of small diameter was the average adhesion less 
than when not bored, while with an increase of the diameter of the 
hole the adhesion increased (—136 : +112.8 : -f 144). 
(G) The most favorable results were given by a T 7 r inch hole (1 :35.4). 
The largest-sized hole gave not much less favorable results (1 : 31.8). 
(7) If the common four-cornered wedge-pointed spike is to be used 
in unimpregnated oak ties, it is best to use a boring-bit of the same 
size as the spjke. 
(8) The results of experiments with 200 spikes on 50 ties would 
allow the conclusion that new oak ties, unimpregnated, and with 
square, wedge-pointed spikes, show the same average adhesion whether 
bored or not; though the boring is recommended, nevertheless, for 
other advantages. 
These results would probably have a like bearing for impregnated 
ties. 
B. For Tine. 
(Probably for other coniferous woods and Chestnut.) 
(1) By using a boring-bit from T 5 ^ inch in size upward, the adhesion 
was increased ; the best results were given by a §-inch hole (1 : 13.5) ; 
and a ^-inch hole was not much less favorable (1 : 10.5). 
(2) When the hole was increased to 5 inches in depth there was a 
decrease of adhesion, though only insignificant. 
(3) In pine ties the place where the spike is driven is of greater im- 
portance than in hard-wood ties, the adhesion diminishing according 
as the spike has more hold in the sap-wood than in the heart-wood. 
