1 SO Chap. XII. Appendix, Part 6. No. 2.

This scum seems to be produced by the fermentation of thewater; after which, it sours, and undergoes decomposition; whichperfects the scum, and makes it separate from the water. Theslower the water moves, the sooner this scum is generated; andstagnant water, in hollows, is the worst for doing so of any; by !which, and the exclusion of the air from the ground, the grassin hollows is very short and sour, as it grows none while it jsthus immerged; and would die altogether, were it not for theheat and air that it gets in the summer months, when the meadowis perfectly dry. This shows the necessity of making up the hol-lows in a water meadow, and of giving the beds in it a goodfalling slope from the feeding gutters to the drains, that the wa-ter may move quickly over the surface: They should be like thesections of the beds described on Plate I, Fig. 2, and as treatedof under Sect. IX. on the formation of a water- meadow.

During the floating season, it is requisite that each meadowshould be inspected at least once in every week or ten days, tosee that the equal distribution of the water is not obstructed bythe continual influx of rotten rushes, or stubble, weeds, leaves,sticks, and the like, provincially called tt •alcr-v.reck, or rack.