272 NOTES—ORIGINAL AND SELECTED.
consideration. The writer says :—"A matter which sooner or later will have
to be seriously considered by various authorities is the gradual filling up of
the Spitway Channel, from the East Swin to the Wallet, and the consequent
impediment to navigation, especially for steamers and laden vessels. During
the summer there were several occasions when the Belle Steamers could not
pass through this Spitway Channel, and had to go a long distance out of
their regular course, to clear the Gunfleet, passing through the Gatway
opposite to Walton-on-Naze, and putting many passengers to much incon-
venience. This closing up of the Spitway, which is termed by some seamen
'a growing up,' appears to be connected with the deposits of London's sewage
in the sea, which, if proved to be the case, should necessitate an alteration of
the system now practised. London sewage is treated by the chemical system,
i.e., the crude sewage is admitted into precipitating tanks, in which it is
treated with lime and sulphate of iron, The matter in solution under the
action of chemicals forms into a solid, which, with suspended matter, settles
in the form of sludge. The effluent product flows into the Thames near
Barking and Crossness, whilst the sludge, to the amount of more than two
millions of tons per year, is conveyed, or supposed to be, to the Barrow Deep,
where it is deposited in the sea. No doubt it was thought that all this
matter would be taken away into deeper water by tides, but there are other
ideas that this is not always the case, and that much of it is drawn by
currents into channels, as the Spitway, where, with other substances drawn
likewise by currents, it settles. Should it be proved that even but a twentieth
part of the deposit is 'currented' to the Spitway, it is easily calculated how
long it may be before traffic through is stopped altogether, and the Gun-
fleet made into a solid bank without any dividing channels from the Buxey to
the Gunfleet Head,"—We shall be very glad to receive facts and opinions
relating to this important question. It seems to be a matter eminently fitted
for investigation by the British Association Committee on Coast Erosion,
from the influence the diverting of currents may have on the wasting and
silting-up of our shores.—Ed.