SPARTINA AND NAVIGATION
is in the phase of youth, and it is too early to say with certainty by what plant or plants its place will be taken.
   Experimental cultivations have already been made in the Medway, in Somerset, at Wells in Norfolk, on the Firth of Forth, and in New Zealand. As the plant has established satisfactorily in these various stations, it is evident that it tolerates a wide range of conditions. Of its capacities as a natural reclaimer much has still to be learnt; in fact, Spartina has as yet hardly begun to be exploited. In due time, no doubt, some agency will be established for its export to distant countries, a desideratum in view of its capriciousness in seed production. It is necessary that experts should be ready on the spot to take advantage of another bumper harvest like that of 1911.
   The effect of Spartina Townsendii upon navigation only time can show. Not that there is any fear of its occupying and blocking navigable channels, for Spartina operates in a higher zone. But the presence of a plant which invades the mud flats, and promises to raise their level to a marked extent, must encroach by just so much on the space formerly accessible to tidal waters. In other words, after Spartina has done its work, less water will flow up the channels than was formerly the case, and less will flow down again. Should this mean a deficiency of scour on the ebb, there is a likelihood of the channels silting up, as has happened in many other cases. As the natural reclamation of many square miles of marsh land would ill compensate for impaired facilities of navigation, it behoves the appropriate authorities to use great vigilance. Carefully planned observations at the present time, or in the near future, should be capable of detecting what may be the trend in this matter, and if trouble is brewing, steps could be taken to restrict or eradicate the Spartina, e.g. by gas poisoning or other chemical agencies. We are referring, of course, to Southampton Water and Poole Harbour.
   Curious as it may appear, the colonization of the mud flats of Poole Harbour is reported to be accompanied at first by an appreciable deepening of the creeks and channels. This effect is probably due to the fact that the travelling silt of the creeks, which formerly moved up and down with the flow and ebb of the tide, is now fixed on the mud flats by the Spartina—the