646 RADICACEOUS ESCULENTS. 



not next the potatoes; then with a coat of six inches or eight inches of 

 soil, and, lastly, with such a thick coating of thatch as shall as effectually 

 exclude both rain and heat, as if ice were to be kept instead of potatoes. If 

 the potatoes are covered up in this manner, when they and the soil beneath 

 them are of a temperature not much above the freezing point, they will 

 keep without sprouting, for any required period ; provided the same care be 

 taken in opening and covering them, when any are wanted for use, as is done 

 in taking ice from an ice-house. To lessen this care, as many as will serve 

 a week may be taken at a time. As ice may be preserved from thawing in 

 an underground cellar, so may potatoes be from sprouting. Whenever 

 potatoes are preserved in a situation that admits of such a rise of temperature 

 as to occasion their sprouting, they ought to be turned over as often as the 

 sprouts have grown to half an inch in length ; otherwise their quality will 

 become greatly deteriorated by the increase of fibrous matter in the tuber, in 

 consequence of the action of the sprouts. Indeed, the best mode is to scoop 

 out the eyes with the point of a knife or gouge (418), or to sear those of the 

 potatoes which are to be kept longest with a hot iron, or to scald or destroy 

 vitality, by putting them for a short time in boiling water, or in a heated 

 oven. Kiln-drying potatoes is a practice not uncommon in some parts of 

 Scotland ; but they should not be afterwards wetted till they are being 

 prepared for use. Every one who knows the difference in the eating of the 

 potato that has, and one that has not sprouted, will admit the importance of 

 this subject. 



1417. Diseases^ insects^ S$c. The potato is subject to the curl in the 

 leaves, which, when it has once taken place, cannot be remedied, but which 

 may, in general, be prevented by using healthy sets from the middle or top 

 end of the tuber, and by good culture in well pulverised soil, dry at bottom. 

 The heating and fermenting of sets, after they have been cut, often produces 

 the curl and other diseases ; and some particular soils and manures seem to 

 be the cause of the scab in the tuber. These diseases, however, are more 

 common in fields than in gardens. A change of variety, or of sets of the 

 same variety from a different locality, is frequently resorted to, more espe- 

 cially in field culture, as a general preventive of disease in the potato. 



Forcing the Potato, see 1100. 



The sweet potato, Convolvulus Batatas, ., has already been treated of in 

 the Chapter on Forcing (1102). 



SUBSECT. II. The Jerusalem Artichoke. 



1418. The Jerusalem Artichoke, Helianthus tuberosusZ/. (Poire de Terre, 

 Fr.) is a corymbiferous tuberous-rooted perennial, a native of Brazil, but 

 sufficiently hardy to thrive in the open air in Britain. Before the potato 

 was known, the tubers of this plant were much esteemed, but they are now 

 comparatively neglected, though in our opinion the Jerusalem Artichoke is 

 as deserving of culture as the common artichoke. The tubers are whole- 

 some, nutritious, and in stews boiled and mashed with butter, or baked in 

 pies with spices, they have an excellent flavour, resembling that of the com- 

 mon artichoke. Two or three rows of a few yards in length are sufficient 

 to afford a small family an occasional dish through the autumn and winter. 

 Propagation is effected by division of the tuber, or by small tubers planted 

 in March : the soil ought to be light, sandy and rich, and the situation open. 

 As the steins grow from four feet to eight feet in height, the rows may be three 



