44 
Boston, Mass. The sap-wood on the ties is only one-half to three quar- 
ters of an inch thick, and quite generally the former. Sixteen or sev- 
enteen of these ties are put under a rail 30 feet long. It is the softest 
and lightest of all the woods considered in this report, but it is found 
to be most durable in service, and, because of its small medullary rays, 
when in the ground does not absorb proportionately as much water 
into its wood-cells as the Hemlock or Chestnut, and after three or four 
years' service is not cut into as rapidly as are the two latter kinds of 
ties. The logs of this wood which have been buried in tke swamps of 
New Jersey for hundreds of years, when cut, rise and float, showing 
that they are not " water-logged." 
This tree has an abundance of small limbs which shoot out near the 
ground and do not die until the limbs and foliage above them shut out 
the necessary supply of light for growth ; then they become dry, but do 
not decay rapidly 5 when they break off it is close to the trunk, the 
wound being healed over at once, as in many other trees ; but it re- 
quires from ten to thirty years to close over the projecting stub. 
In many cases spores of higher fungi (Hymenomyeetes) and the spori- 
dia of some species of the Spluvriacei find lodgment on the bark of 
the broken limbs, and finally a growth is extended to the heart-wood. 
But on account of limited supply of air the decay thus set up is very 
slow, and it follows up and down the wood-cells, spreading laterally 
very little. Thus the decayed tissue may extend considerable distance 
in the timber and yet not exceeding one-half or an inch in diameter. If 
the wound finally becomes closed and the air supply cut off, all fungous 
growth is checked, if not fully arrested. 
Durability. — On account of its softness and natural durability, this 
wood has not been treated to any extent to preserve it for ties. The 
spikes do not hold in it as well as in some of the harder woods, yet it is 
very valuable for the above-mentioned traffic, and its use is on the in- 
crease. The rings do not separate as freely as those of the Yellow Pine, 
and the cutting down of the fibers is due largely to abrasion; the spikes 
draw, and from the looseness of the rails, together with the sand and grit 
between them and the ties, the fibers are crushed by the passing of 
every train. Could the rails be kept tightly spiked, the cutting would 
not proceed so rapidly. For a trunk-line freight traffic the White Cedar 
tie is too soft for the present 65-pound rail with only a 4 J- to 4J-mch 
base. In order to save the Chestnut ties for their curves, roads of light 
traffic are now commencing to replace these on their tangents with 
Cedar. 
FUNGI. 
The species of fungi that attack this wood are but little known. In 
searching for them on the Boston and Maine Bailroad, from Boston to 
Portland, I found specimens in fruit of only Agaricus cam pan ell a, 
Batsch , which has a tawny pubescence at the base. Agaricus melleits 
Vahl., has been said to attack this wood, but I have never been able to 
find it either on the prostrate trunks or on the ties. 
