COLLECTIONS AND RECOLLECTIONS. 
315 
I have seen the Ammonical Coal-Gas tried to destroy the pine-bug, 
as recommended by a gentleman in Ireland, in a report to the Gar¬ 
deners’ Magazine. The gas destroyed all the bugs that were on the 
leaf of the plants, but those which were in the soil among the roots, 
and about the neck of the plant at the surface of the pot were not 
the least affected, and in a few days they crawled from the root on 
the leaves, when the plants looked as filthy as before the gas was ap¬ 
plied. I therefore consider the gas no cure whatever. 
I now come to a description of Mr. Witty’s Smoke Consuming- 
Furnaces. When I was gardener to Ralph Naters, Esq. Sandy ford 
Lodge, near Newcastle, he had two hot-houses for pines and vines 
to the rafters, their furnaces were on Mr. Witty’s construction to 
consume smoke. The furnaces are fifteen inches wide, and fourteen 
inches high, the bars twenty inches long. On each side of the fur¬ 
nace there is a cavity or air-flue twelve inches high and three inches 
and a half wide with a door. This cavity or air-flue is separated from 
the fire on each side with a brick in the bed, till it come to the throat 
of the flue at the end of the bars where both cavities are open : the air 
circulates along the cavities, and stagnates the smoke as it evaporates 
from the fire. By that means the smoke cannot escape so quick along 
the flue as it does in what is termed a good burning furnace, and till 
the circulation of air the fire draws from below the bars, and the 
strength of smoke overpowering the air passing along the cavity, the 
smoke escapes out of the chimney in a slow manner, a much whiter 
colour than it does from the common fires. But I always could ob¬ 
serve as great a quantity of smoke from them, which made me dis¬ 
trust any of the smoke being consumed, and the flues were sooner 
choaked with soot than the other flues. When the air-flue or cavity 
door is kept shut, the fire burns nearly the same as other furnaces; 
but as they save no fuel, and create more trouble in cleaning the 
flues, I consider them a disadvantage rather than an improvement. 
William Grey. 
Bconfront, near Hexham, Northumberland . 
The Beech Tree, a Conductor of Lightning. —In Vol. 1, 
page 739, I observed some remarks by Omega, on the non-conduct¬ 
ing properties of the beech. Omega states, that he had never been 
able to trnce a single instance, in this or any other country, of the 
the electric fluid striking the beech tree. An instance or two have 
come under my own observation, which, I think, afford sufficient 
proof that it is nearly, if not altogether an equal conductor with 
other trees. In the year 1821, or 1822, I do not recollect which, 
two very large beech trees, belonging to the Right Hon. Lord Gren- 
