322 On the Porosity of Wood. 
zable matter which, whilst its powers remained perfect, would have 
generated an oak branch, will when debilitated, give existence to 
various species of Fungi. 
A dry season after hay harvest, parching up tlie eddish grass, 
being succeeded by warm showers, occasions a great Mushroom sea- 
son, as in this year, 1831, when there was the greatest quantity ever 
known. One man frequently brought 200 pecks in a cart, from 
Ashbourne to Shefl&eld. September and Octx)ber were the plentiful 
months. It is observed that the eddish this year is generally very 
indifferent on limestone land, and not good for cattle. Where the 
eddish was much burnt, as about Ashbourn, Mushrooms on the 
limestone soil were most plentiful, but where the eddish was good 
on shale land, which is retentive of moisture, few or none appeared. 
In the years 1818 and 1826, the eddish on limestone was much 
■burnt, and these were great mushroom seasons. 
Yours, respectfully, 
Bakewell, Nov. 29, 1S3\. White Watsqx. 
Article III. — On the Porosity of Wood, and Effects of 
Copper on Vegetatioti. Commimicated by F. J. G. W. 
Gentlemen, 
t)n perusing the Glasgow Mechanics' Magazine, I have met 
with the following remarks, which you may not perhaps consider unwor- 
thy of admission into the pages of your. invaluable Register. 
On the Porosity of Wood. — *'The porosity of wood is so remarkable 
that air may be transmitted in a profuse stream, by blowing with the 
mouth through a cylindric piece of dry Oak, Beech, Elm, or Birch, 
about two feet long. If a piece of wood or stone be put in water, and 
placed in the receiver of an air pump, by withdrawing the external air, 
the air which has been scattered through the pores of these bodies will 
issue from every point of their surface, and rise in a torrent of bubbles. 
In like manner, Mercury is forced through a piece of dry wood, and 
made to fall in the form of a shower." 
Effects of Copper on Vegetation. — "Some time since, (says Mr. 
Phillips,) I accidentally spilt some solution and Oxide of Copper near 
the root of a young Poplar tree. In a short time the tree began to 
droop; the leaves on the lower branches dying tii-st, and eventually 
those on the upper ones. On cutting a branch from the tree I observed 
that the knife was covered with Copper, and the whole breadth of the 
branch, showing that the Copper had been absorbed, and had undoubi- 
tedly proved fatal to the life of the tree. 
F. J. G. W. 
