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two centuries elapsed before it was generally cultivated as a fiekl crop. 

 In Scotland the first yield of potatoes was planted in the county of 

 Sterling in the year 1732. 



It has been ascertained by chemists that the potato contains seventy 

 parts of water and thirty parts of farina, or pure starch, in every hun- 

 dred parts. According to an analysis made by the distinguished Sir 

 Humphrey Davy, the avoirdupois pound of seven thousand grains of the 

 black kidney potato contained : 



Of soluble mucilage, OVO grains. 



pure starch, 695 " 



fibre, 622 « 



water, 4,Vl3 " 



There are numerous varieties of the common potato, which are dis- 

 tinguished by the shape of the leaves, the color of the flowers, and the 

 general appearance of the hanlms or veins. The tuberous roots, which 

 alone is the object of cultivation for food, diflfer essentially in the quan- 

 tity and quality of the farina which they contain ; some being of a fine 

 mealy quality, while others are of a waxy, disagreeable flavor. Potatoes 

 however, of the very best quality, may become deteriorated by continuous 

 planting on old, exhausted, or clay soil^, deficient in humus or vegetable 

 mould, while tubers deficient in farina may be greatly improved in qual- 

 ity by being planted in virgin soil in which humus abounds. 



The potato, in common with all tuberous and bulbous plants, has two 

 ways of reproduction ; the one by the multiplication of its roots, and 

 the other from the seeds. The first mode is that most generally prac- 

 ticed ; the latter method is that by which new and important varieties 

 may be originated. As this process, however, is tedious, and the re- 

 sult, as regards quality, is very uncertain, farmers, instead of fret- 

 ting away valuable time in this reno\ating process, would consult, 

 perhaps, their interest in leaving this department of labor altogether in 

 the hands of the horticulturist or the market gardener. A superior po- 

 tato, however, has frequently been produced by crossing. This is 

 done by simply selecting two good varieties and taking the pollen from 

 flowers of one variety and dusting it upon the pistils of the others, by 

 which means the good quahties of both kinds are frequently united in 

 the tubers produced. Potatoes may also be propagated by planting 

 slips from the vines ; shading them for a short time from the rays of 



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