FOUND BY THE ARCTIC VOYAGERS. 35 
tainly either Pine or Spruce, the Larch employed in small quantities 
consisting principally of young trees split lengthwise. I have been 
quite surprised to find how very soon the weather acts upon fabricated 
wood when fully exposed to sun and rain. Specimens of Oak which 
had been roughly cut out only three months since are in parts as much 
bleached as if they had been subjected to the wash of gravel for as many 
years ; and the same may be said of the other kinds of wood mentioned 
above, especially Larch, the dates of their fabrication varying from three 
to fifteen months. In all these cases vegetation, with a single excep- 
tion, closely allied to that on Captain Penny’s piece of English Elm, 
is very evident, and in a greater or less degree of perfection according 
to the more or less recent fabrication of the materials. In these in- 
stances however an agency has existed, which would not at first have 
been suspected. After a careful examination of all the most marked 
cases of bleaching of the woody fibres, I have satisfied myself that the 
external structure has been deranged, and more fully subjected to the 
bleaching influence of sun and air, by wasps and other insects; and 
this indeed accounts for the very rapid change of colour which has 
taken place even in the hardest woods, for where the surface remains 
much in the same condition in which it was left by the saw, the fibres 
are in general but slightly bleached, except in the softer woods. 
In all the cases where insects have been at work on sound wood, 
fungi have established themselves on the bleached fibres. How far 
they have co-operated it is difficult to say, but not only are the fine 
threads of their mycelium to be found creeping over and between the 
constituent cells, but the cells themselves are frequently gorged with 
the mycelium, which must have lived at their expense and exercised a 
very powerful influence in their disorganization. And this I find to be 
the case in all bleached wood, whether the bleaching has taken place 
from pure circumstances of climate, as in the Arctic piece of Elm, or in 
planks exposed here in the early portion of the year, when there could 
be no other agent of the disintegration of their surface than atmosphe- 
ric conditions, or in others fabricated in summer, which have been 
abraded by insects for the structure of their nests. 
Besides this general bleaching, which, according to circumstances, 
takes places more or less rapidly, there is a partial bleaching, which 
every one must have observed. It is almost impossible to find a rail 
which has been exposed for any length of time without observing more 
