39 
portions of White Oak ties as a rule follows closely upon (hat under the 
rails, especially that portion of the tie which is surrounded by or under- 
neath the ballast. In gravel ballast, oak ties decay more rapidly under 
the ballast than in fche fully exposed parts. In most localities the de- 
cay of the oak is retarded by imbedding the tie in the ballast as little 
as is compatible with the stability of the track. The layers of wood 
under the rails separate from each other by the breaking-through 
of the tracheids between the large duets, yet not as readily as in the 
Chestnut, but the massive bundles of medullary rays of the oak to some 
extent check the breaking or crushing of the tracheids, and oiler con- 
siderable resistance to the undulation of the rails and consequent abra- 
sion of the ties. The apparent injury to the White Oak ties by spik- 
ing is not as great as it, is to the other woods under consideration, but 
it is sufficient to shorten, to some extent, the life of ties used. Boring 
holes for the spikes would prevent much checking of the wood, and a 
proper-sized hole would increase the adhesion of the spike, as shown by 
tests.* 
Time of cutting ]\ltitc Oak for ties. — The season of cutting affects the 
heart-wood much less than it does the sap-wood. Great care must be 
taken of timber cut from April to July, as the large amount of sap elab- 
orated at this time furnishes a favorable condition for the deyelopment 
of fungi, first involving the sap-wood and then the heart- wood. For a 
like reason care must also be taken of timber cut from July to Novem- 
ber, as the sap-wood is liable to be affected; but timber cut in winter is 
less liable to attacks of fungi at once, from the fact that as a rule the 
temperature is too low for such growths, aud the wood is more likely to 
get partly seasoned than if cut in the summer.f 
PRESERVATION. 
This has been accomplished by "Kyanizing" and ^^ Bnrnettizing ,, 
and by the use of copper sulphate. But the treatment must be long- 
continued to insure full penetration into the wood : otherwise it will 
be a failure. 
Fungi. 
The sap-wood of White Oak ties in the ground is quickly attacked by 
Polyporus versicolor, Fr., the fungus often being found fruiting on tim- 
ber in the main tracks. The past season I have found it growing to 
some extent upon the heart- wood of this class of ties, showing that 
under favorable conditions it can destroy the heart- as well as the sap- 
wood. 
Bcedalia quercina, Pers., is often found growing on the sap-wood of 
these ties, and destroys them with considerable rapidity .{ Polyporus ap 
planatus, Fr., attacks the heart-wood, and is very destructive, though 
* See Table VI. on Adhesion of Spikes, p. 58 ; also note an<l tables on p. 62. 
t See foot-note, p. \\7 . 
X Prof. Charles II. Feck thinks it cannot bo quercina, as he has not been able to 
find any specimens of this species. 
