The crops in Ireland, where the potato is the principal object of culture, vary from 11/2 to 101/2 tons per acre, according to the season; but in the average of three years ending 1849, the annual growth of Great Britain and Ireland amounted to nine million tons, which, at L3 per ton, exhibits the value at L27,000,000 sterling.  Ireland produced in 1847 a little over two million tons, the yield being 71/4 tons per acre.  In 1848 the produce was 2,880,814 tons, averaging only four tons to the acre.  In 1849, 4,014,122 tons, averaging 51/2 tons to the acre.  In 1850, 3,954,990 tons; and in 1851, 4,441,022 tons; the average yield per acre not stated.  In many parts of Scotland 24 tons to the acre are raised.  The sales of potatoes in the principal metropolitan markets exceed 140,000 tons a year, which are irrespective of the sales which take place at railway stations, wharfs, shops, &c.  The imports into the United Kingdom average about 70,000 tons annually.  Potatoes are exported to the West Indies, Mediterranean, and other quarters.  For emigrant ships, preserved or dried potato flour is now much used.

The following quantities of potato flour were imported from France in the last few years:—­

Cwts.
1848      17,222
1849       3,858
1850      12,591
1851       2,631

We also imported the following quantities of potatoes in the last five years:—­

Cwts.
1848          940,697
1849        1,417,867
1850        1,348,867
1851          636,771
1852          773,658

Thoroughly dried potatoes will always produce a crop free from disease.  Such is the positive assertion of Mr. Bollman, one of the professors in the Russian Agricultural Institution, at Gorigoretsky.  In a very interesting pamphlet[47] by this gentleman, it is asserted, as an unquestionable fact, that mere drying, if conducted at a sufficiently high temperature, and continued long enough, is a complete antidote to the disease.

The account given by Professor Bollman of the accident which led to this discovery is as follows:—­He had contrived a potato-setter, which had the bad quality of destroying any sprouts that might be “on the sets, and even of tearing away the rind.  To harden the potatoes so as to protect them against this accident, he resolved to dry them.  In the spring of 1850, he placed a lot in a very hot room, and at the end of three weeks they were dry enough to plant.  The potatoes came up well, and produced as good a crop as that of the neighbouring farmers, with this difference only, that they had no disease, and the crop was, therefore, upon the whole, more abundant.  Professor Bollman tells us that he regarded this as a mere accident; he, however, again dried his seed potatoes in 1851, and again his crop was abundant and free from disease, while everywhere on the surrounding land they were much affected.  This was too remarkable a circumstance not to excite attention, and in 1852 a third trial took place.  All Mr. Bollman’s