272 NOTES ORIGINAL AND SRLKCTED. 



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 c.ise, 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. 



