320 On the Failure of the Potato Crop. 



weighing about four ounces. These should be taken and hiid thinly on a piece 

 of clear ground, or on short grass, where they sliould remain at least tlu-ee 

 weeks, exposed to the action of tlie sun and tlie air night and day, and longer, 

 should the weather permit, luitil they become quite green. If there be any 

 fear of frost, they must be covered over with a tliin covering of straw, to pre- 

 vent tlie frost from injuring them ; but the covering should be taken off again 

 as soon as a change of weather takes place. While they are thus lying on the 

 ground, let them be watered over twice a week with a solution of saltpetre 

 and water in the following proportions : in ten gallons of s[)ring or river-water, 

 dissolve half a pound of saltpetre, and let this be applied by a watering-pan 

 with the rose on." [The intention of tiiis solution, Mr. Stent informs us by 

 letter, is to harden the skin of the potatoes, and thus to strengthen their vege- 

 tative powers, by keeping them perfectly dormant.] " When they have lain 

 in this state about ten days, it would be advisable to turn them over ; and, 

 after remaining the time before specified, a place should be prepared to pie 

 them down for winter ; which should be done, if possible, in a shady situation 

 on the north side of a building or high hedge. A circular piece of ground 

 must be cleared about 8 ft. in diameter, in the centre of which must be placed 

 the ventilator, as represented in the plate." [This ventilator is a tube, 6 in., 

 or 8 in., or a foot square, the sides being formed of strips of wood, 2 in. broad, 

 and 1 in. thick, with openings between the strips 2 in. wide : below, it com- 

 municates with an air-drain made under the floor of the heap, and above with 

 a cap, which may be taken off, or |)ut on, at jileasure. The same principle is 

 extensively employed in Scotland, in ventilating corn-ricks which have been 

 put up late in the season.] " This should be kept perfectly upright, and the 

 potatoes placed round it, tiie quantity not to -^r^Jceed thirty or forty bushels- 

 This being done, the next thing will be to cover the whole down neatly with 

 straw, not more than 2 in. thick. In this state let them remain a week or ten 

 days, or more, according to the mildness of the weather; then cover them 

 about 6 in. thick with eartii, keeping the ventilator continually open at the top, 

 except in severe frost, when it can be easily closed by a whisp of straw or hay. 

 The whole of the sides of the pie might be covered down with litter, or potato 

 tops : in this state they may remain until the weather becomes more severe, 

 when the litter may be taken off" and about Gin. more of earth added, and the 

 whole beaten well "down with a sjiade. After this the litter may be replaced, 

 every person exercising his own judgment whether this covering should be 

 increased or diminished, according to the state of the weather ; that is to say, 

 in mild winters the covering might be diminished, whereas in very severe 

 winters it will be necessary to increase it. 



" The advantages of the ventilator will be seen by its allowing the evapora- 

 tion to pass oft" the whole depth of the pie : by this means the potatoes will 

 be kept in a cold dormant state, and will not grow until the time of planting ; 

 consequently, the centre eye will be preserved, which will always grow the 

 first and the strongest ; and therefore the potato, possessing all its inherent 

 powers of vegetation, must, of course, make a much stronger shoot than those 

 which have been previously exhausted as before described." (p. 14.) 



The rationale of the progress of the young plant is tims 

 given : — 



" From the base of this shoot immediately proceed the fibres or roots which 

 support the ensuing plant in an horizontal direction. Above these proceed, 

 in the same direction, the laterals, or side shoots, which produce the tuber or 

 potato; and, as soon as the fibres are sufficient to support the shoot, the 

 original plant is of no further service : the fibres then become the sujjport of 

 the plant. Now, it is evident that the tuber, or potato, receives its nourish- 

 ment or support from the sap, which passes in the main stem from which 

 these laterals proceed. This operation is carried on by the ebbing and flowing 

 of the sap, and is caused by attraction and repulsion, which depend upon the 



