==General Cultivation.==—­As soon as the shaws appear the ground should be hoed between the rows, and if there is any fear of frost the shaws should be lightly moulded over.  As the growth advances the crop must be earthed up, care being exercised not to earth up too much, for, taking six inches as the best average depth, the crop will be diminished by an increase beyond this depth.  One urgent reason for early work between the rows is that a prosperous crop will soon put a stop to it.  The moment it becomes likely that the shaws will be bruised by traffic between the rows they must be left to finish their course in their own way, because the formation of tubers below will be in the ratio of the healthy growth above ground.  The Potato may be said to be manufactured out of sunshine and alkaline salts.  The green leaves constitute the machinery of the manufacture, for which the solar light from above, and the potash, phosphate of lime, phosphate of magnesia, and phosphoric acid from below are the raw materials.

==Change of Ground and Seed.==—­In common with all other crops, the Potato needs as often as possible a fresh soil, and a renewal of seed from some distant source.  The need for a change of soil is made apparent by an analysis of the root, which contains large proportions of potash, phosphorus, and sulphur, with smaller proportions of magnesia and lime, without which the plant cannot prosper.  A succession of heavy crops of Potatoes on the same land may be said to take from the soil its available potash and phosphates, and this crop will not, like some others, take soda instead of potash when the last-named alkali runs short.  Here then is a chemical reason for change of soil.  Another reason is found in the history of the species of fungi that prey on the Potato when its growth is checked by heavy rains and a low temperature.  These leave their spores in the soil, like wolves hiding in ambush, to destroy the next crop.  They are powerless to attack any other crop; therefore a suitable rotation gives them time to die out and leave the land clean as regards the =Phytophthora= and other parasites that destroy Potato crops.  The necessity for an occasional change of seed rests on old experience, and should scarcely need enforcing.  One word may be said here by way of explanation, and it is this:  the seed house that aims to put a good article in the market adopts measures which altogether differ from those followed by the majority of persons who have not been trained to the business.  It is a common experience to find that those who save their own seed from year to year have as a result a constantly declining strain, so that every year the growth is weaker, less true, and less profitable.  It is so all through, but is especially the case with Potatoes.  We do not say that all who save their own seed act unwisely, for some are most expert in the business.  But we do say that seed saving is not learned in a day, and many who think they save shillings when they save