428 Account of a Volcantc Eruption in Iceland. 
to put the cost at the highest point, more strongly to enforce the 
advantage resulting from the practice, as it thus leaves nothing 
to object to. 
This field had in the last course 30 tons of manure; it is 
strong clay. First crop, potatoes, product 26 hundred stone 
per acre: sown with wheat and clover; both these crops were 
admirable. The oats this last year are calculated to produce 
60 Winchester bushels per acre; it is now preparing for green 
crop again, and to have 50 tons of manure per acre. Admitting 
the green crop to profit three pounds per acre by the drainage, 
which is only half what was lost at average prices this year on 
the Swede crop, this on the 50 acres would be one hundred and 
fifty pounds: calculating it to yield three Winchester bushels per 
acre more of wheat, at 7s. per bushel, this would be fifty-two 
pounds ten shillings and ten-pence per acre; for the clover for 
two years 50/. more, making a probable increase of produce, 
without any extra expense, of 2521, 10s. Thus, in a five years 
course the whole expense will, in all probability, be repaid, and 
an annual permanent increase of rent to the amount of 60 per 
cent. gained. 
Wet is more destructive to pasture than it is to grain and green 
crops; and as pasture is the mest material object near to towns, 
draining, in such situations, is a more profitable improvement 
than in any other situation, and will consequently justify a greater 
expense. 
When once dry land is well laid down to pasture, the improve- 
ment is permanent. If flooded with water, it cannot remain for 
any length of time in pasture, but must be again brought under, 
tillage. On wet soils, improvement is almost labour in vain— 
costly at all times, but now ruinous. 
Should the Society deem this undertaking as meriting their 
attention, it will be highly gratifying to me, who owe them many 
and great obligations. 
The ambition of meriting the honour of their rewards, first 
directed my attention to agriculture, and I trust the result has 
not altogether been without its advantages to the public. 
I am, sir, &c. &c. 
JoHn Curistian CURWEN. 
LXXXVII. Account of a Volcanic Eruption in Iceland. By 
Dr. ForcHHAMMER*, 
Tu E very low state of the barometer throughout a great part 
of Europe in the months of December and January, although not 
* From Annals of Philosophy, No, 18. 
immediately 
