M‘Sweeny, on the Climate of Ireland. 231 
power of the sun was then greater than it is at present, as it had then more obstacles 
to overcome in warming the surface of the island. 
The vast quantity of manured fallow ground, of a colour dark in proportion as it 
is not exhausted by severe cropping, now materially aids the sun, to warm the surface 
of Ireland in the winter. It is well known, that the exhausting of ground by repeated 
corn crops, causes its colour to become lighter. This injudicious system, was much 
more practised formerly, than at present. Landlords everywhere endeavour to pre- 
vent it. The old country people are positive in asserting, that the snow lay longer on™ 
the ground when they were young, than it now is observed to remain. 
If, notwithstanding luxuriant crops from an improved soil, and the shading of the 
surface by the general cultivation of the potatoe, and by the number of hedge rows, 
it should be contended, that on an average of years, the summers now are ewactly as 
warm as they were formerly, it would imply, that the power of the sun’s rays is greater 
for warming the island now, as its surface is better shaded than it was in the period 
subsequent to the destruction of the woods. 
The greater power in the rays of the sun, on an average of years cannot be admitted, 
as there is no evidence to prove it ; and the occasional return of very hot summers, and 
of very severe winters, is attributed to causes at present not perfectly understood. 
If this reasoning be allowed, it must be admitted, that the modification of climate 
must have kept pace with agricultural improvement, on an average of years, and it 
explains, and corroborates popular opinion on the subject. 
The vast increase of the potatoe culture, and the general use of this vegetable as 
the entire dependence of the peasantry, have been within the memory of the old per- 
sons of the present generation; therefore it is just to believe, that a modification of 
climate from local causes, has taken place within their recollection. 
The general character of the climate has been the same from a very early period ; 
hot summers, and cold winters arise from géneral, not from local causes; but when 
they do happen, the temperature must be influenced by the state of the surface in 
some degree. 
The testimony of the peasantry, that the snow does not remain now so long on the 
ground as formerly, must be received. The experience of old sportsmen, who had 
heen in the habit of traversing tracts of country now reclaimed, corroborates the eyi- 
dence. 
In Rutty’s time, the cultivation of the potatoe was making progress on the rough 
grounds, in the county Dublin; he admits that his account of frost and snow in the 
city of Dublin, was too little when compared with the accounts of country parts. 
On account of the scanty state of data on the weather in Ireland, it is impossible to 
put popular opinion to a severe test, by scientific records. 
In fact if it be true, as was supposed by Lord Bacon in his time, and as is imagined 
by Howard and others, that the seasons go through a cyele, it is evident that we 
