RECENT DREDGING IN CATTEWATER. 403 
These figures show great variation in amount of suspended 
matter, mineral and organic. 
The mean organic matter half -flow tide is 1*498 per 100,000 
parts. 
The mean organic matter half-ebb tide is 1*302 per 100,000 
parts. 
The greater amount in the incoming tide is probably due to the 
sewage outfall in Deadman's Bay. 
Half -flood Tide.— The total mean suspended matter on the 
surface at the 
East end . . . 8-660 per 100,000 parts. 
West end . 9*878 
As the east and west ends are 100 yards apart, 1*218 parts in 
100,000 had apparently settled whilst travelling that distance. 
Half -ebb Tide. — The total mean suspended matter on the 
surface at the 
East end 9*472 per 100,000 parts. 
West end . . . 7*290 
So that on the ebb 2*182 per 100,000 parts is apparently 
deposited. 
Half -flood Tide. — Twelve feet from bottom the total mean 
suspended matter at the 
East end 11*518 per 100,000 parts. 
West end . . . 9*616 „ „ 
This is reversing the usual order; for the west end should be 
more than the east end. 
Half -ebb Tide. — Twelve feet from bottom the total mean 
suspended matter at the 
East end 14*323 per 100,000 parts. 
West end . . . 9*671 „ „ 
It will be necessary to extend these experiments before any- 
thing very definite can be learnt from them. Observations 
made when heavy freshets are coming down will be especially 
valuable. 
Cattewater compares favourably, as regards suspended matter 
with some other tidal and fresh-water rivers. 
