406 On the Culture of the Potatoe. 



The soil in which I proposed to plant being very shallow, 

 and lying upon a rock, I collected it with a plough into high 

 ridges of four feet wide, to give it an artificial depth. A deep 

 furrow was then made along the centre and highest part of 

 each ridge ; and in the bottom of this, whole Potatoes, the 

 lightest of which did not weigh less than four ounces, were 

 deposited, at only six inches distance from the centre of one to 

 the centre of another. Manure, in the ordinary quantity, 

 was then introduced, and mould was added, sufficient to cover 

 the Potatoes rather more deeply than is generally done. 



The stems of Potatoes, as of other plants, rise perpendi- 

 cularly under the influence of their unerring guide, gravitation, 

 so long as they continue to be concealed beneath the soil ; 

 but as soon as they rise above it, they are, to a considerable 

 extent, under the controul of another agent, light. Each in- 

 clines in whatever direction it receives the greatest quantity 

 of that fluid, and consequently each avoids, and appears to 

 shun, the shade of every contiguous plant. The old tubers 

 being large and under the mode of culture recommended 

 rather deeply buried in the ground, the young plants in the 

 early part of the summer never suffer from want of moisture ; 

 and being abundantly nourished they soon extend themselves 

 in every direction till they meet those of the contiguous rows, 

 which they do not over-shadow on account of the width of 

 the intervals. 



The stems being abundantly fed, owing to the size of the 

 old tubers, rise from the ground with great strength and lux- 

 uriance, support well their foliage, and a larger breadth of 

 this is thus, I think, exposed to the light during the whole 



