1884.] EDITORS BOX. 447 



THE FORMATION OF DEW. 



Sir, — In your last issue (p. 360) Mr. David Cannon talks of dew 

 being intercepted by trees, grasses, &c., before it can fall to the ground ; 

 and this naturally suggests the question, How and where is it formed 

 in the air so as to fall to the ground ? 



I have been told that on light, sandy soils covered with a crop of 

 good grass, on a clear, still night, the grass may be quite wet with dew 

 in the morning ; and that at the same time a fallow field of the same 

 soil adjoining it may be without a particle of dew having fallen upon it. 



I am also told that everything may be in favour of a heavy fall of 

 dew in the evening, and yet, if a severe gale of wind sets in and 

 blows all night, there may be no dew in the morning in either the 

 supposed grass or fallow fields. 



Perhaps Mr. David Cannon, or some one of your numerous readers, 

 will be so good as to explain these phenomena. 



Dunrohin, Golspie, KB. D. M'Corquodale. 



[Dew is simply the deposition, in liquid form, of the moisture in 

 the air. Blades of grass radiate, or give off, their heat more quickly 

 than earth, and hence moisture is more readily deposited upon them 

 than upon the ground in a fallow field. The absence of dew on a 

 windy night is occasioned by the dissipation by the wind of the 

 atmospheric moisture. — Ed.] 



BE-PLANTING. 



Sir, — Would you favour Lord Castletown with your advice, on 

 cutting a Scot's Fir wood, and replanting the ground with another 

 crop of the same kind? The wood has been planted about thirty-five 

 years, and it is now fit to be cut over and disposed of. The l.ind is 

 principally bog. Would you advise planting next season, or letting 

 it rest, say, for three years before planting ? Lord Castletown will 

 feel grateful for any remarks you may make on the subject. 



Lisduf, Queen's County. Samuel Brady. 



[As soon as the crop is cut down and removed from the ground, 

 including all that may be useful for fuel, let the ground be carefully 

 gone over and cleared of twigs, chips, bark, and any other woody 

 matter. Collect these into heaps with a rake, where the nature of 

 the herbage will permit the use of it, and burn every morsel of them ; 

 taking care not to set the bog on fire, if it is in a dry state. Clean 

 out the drains, and cut fresh ones where they are required, spreading 

 the cast-out moss over the ground. If the land was weU-drained for 



