Many such wide stretches of meadow occur on the banks of the Severn, as in the neighbourhood of Gloucester, Tewkesbury, Worcester, &c., where they get the name of _Ham_. It is much to be regretted that these hams are not made the most of, for the same reason as applies with respect to common, for the want of some efficient officer to direct improvements; and so from the water here and there stagnating good herbage is ruined, and from the floods not being controllable, even hay is lost with the summer freshets. But where such land is vested in single enterprising proprietors, not only is drainage insured, but embankments are made to keep out the waters when not required, as so much met with on the banks of the Thames; and such fields are at once an evidence of the capabilities of river flats, and the great importance of individual enterprise. 4. The last case approaches very nearly to that of _irrigated_ meadows; but these latter are mostly situate on small streams, which can be directed to flow through, not over them, at any time: they offer a most important means of augmenting our pasturage in certain districts, and will therefore receive a chapter to themselves. 5. Permanent grass enclosures are of very varied sizes, from hundreds of acres, forming perhaps a park, to the small meadow of the homestead; they may be seldom or never used for haymaking, but most of them are aimed up for hay once, twice, or thrice in four or five years. These form the greater part of the grass-lands of our country, and are indeed nowhere greener or more productive than in the British Isles; still, as we are an advocate for their cultivation—which, if it does not quite realize the position of making two blades of grass grow where one grew before, may at least do much in this direction—we shall reserve further remarks upon this subject until we have particularly analyzed the contents of a meadow. 6. As shifting crops, grasses, and other fodder plants may be made exceedingly useful, these may therefore well occupy a chapter to themselves. CHAPTER X. ON THE SPECIES OF MEADOW-GRASSES. Although we possess more than a hundred species of native grasses, we shall rarely find a fourth of them even in a wide range of meadows; and if we do so, it is rather an argument against than in favour of the quality of their herbage, as, so few are the best grasses in number, that it is almost a law for the best meadows to contain the fewest species of true grasses.