£5$ Mr Black adder on the condensation of Humidity. 
Fig. 2 . Observed at the sea shore. The house was within thirty 
paces of high water-mark, and nothing interrupted the view 
to the most distant horizon. The sky was very clear ; the 
wind gentle and northerly. 
Fig. 3. Observed at the same place as fig. 2 ., the window having an 
opposite direction, and being about 15 feet from the ground. 
The latter gradually rose as it receded, so that at the distance 
of a gunshot, it was higher than the house, which was of three 
stories. 
Fig. 3. Observed in a house situated on the northern verge of Edin- 
burgh, the window being about 20 feet from the ground, and 
the view in front and to the left uninterrupted. At some dis- 
tance to the right there was a row of houses, which partially 
interrupted the view in that direction. The sky very clear, — - 
no clouds, — the wind N. E., — a gentle breeze. On the out- 
side, and to the under and middle part of the upper sash of 
the window, was suspended a bent instrument, one-half of 
which was of metal, the other of glass ; and the spheroidal me- 
tallic ballon the longer stem, which had a diameter of about two 
and a-half inches, was two inches distant from the glass of the 
window. Opposite to this metallic ball, in the line of direc- 
tion of the wind, there was a somewhat oval shaped spot on 
the pane of glass, perfectly free of moisture, and this spot had 
a dfameter equal to about one-half that of the ball. On the 
same level with the instrument referred to, and close to the 
side of the window, was attached a screen of polished tin- 
plate, having the form of a half cylinder, and in which were 
suspended a thermometer and hygrometer. On the pane of 
glass, immediately above the tin-plate screen, the otherwise 
regular form assumed by the moisture is obviously modified. 
Art. IV. — Account of the principal Coal Mines in France^ and 
the quantity of Coal which they yield. 
JEngland and Scotland contain the most extensive coal-works 
that exist in the world. They are there very numerous, being 
in the direct ratio both of the enormous consumption of Great 
Britain, and of the great annual exportation. Several of these 
immense mines present the union of the greatest moving powers 
that can be imagined, and of the most simple and most econo- 
