407 C 32 ] 
jminute, for evaporation and sosikage, and ajlowing this canal to be 
double width, and usual deptli above tide 
58.13 X 16 X 60 X 12 hours = 669,600 per day. 
Lockage three locks per hour, cubic feet, 30,000 2,160,000 
Cubic feet per day 2,829,600 
The reservoir would, therefore, provide for 1 1 1 days an {additional 
depth of five feet. 
These calculations are intended to show the importance of an accu- 
rate survey of Herring Pond, and an investigation of its capacity and 
capability of being converted and improved into a reservoir. 
Although not charged with the duty of making an estimate of the 
expense of this work, it may be acceptable to the Department to learn 
what estimates have been made on former occasions. These appear 
to be respectively as follows: 427,000 dollars, 417,000 doUars, 
492,000 do'Uars, 400,000 dollars: the latter including three steam 
boats for towing the vessels and breaking the ice. Their (j'an did not 
probably include the breakwater antl some other particulars referred 
to: nor a canal of those noble dimensions wo have been supposing. 
The w inter, if very severe, may close the canal for a short time. 
It is A cry rare that Boston harbor is closed, ex en for a short time. At 
such times the active exertions of steam boats, equipt with ice-break- 
ers, as suggested by Mr. Jones, for the Delaware, would keep Ba€k 
River Harbor clear, and one whicli should break up the ice m the 
canal, would also be useful in assisting vessels througli against the 
wind. 
Some apprehension has been entertained tliat sand might accunui 
late at the entrance of Barnstable Bay. It appears, on inquiry, 
that tliere is a constant progress of some sand from west to east, from 
Momunent Point; and from southeast to northwest; also from the 
same towards Plymouth, and by this coarse, Scusset Creek had been 
gradually gaining east. In twenty -two years it was said iis mouth 
had shifted 300 yards, but there can be nothing to appi'ehcnd from this 
cause, since, by allowing the canal to drain off occasionally, its en- 
trance would be cleared, but the operation of the lock would alone 
keep it so. 
Some few general remarks upon the navigation may not be mis- 
placed. 
The harbors on Barnstable Bay arc Province-town and Wellfleet, 
for large vessels; Barnstable is accessible at all times foi' coasting 
vessels: Plymouth is accessible also for large Acssels on the west 
side. 
In coming up Buz/iU'd's Bay there are three or four good shin 
harbors. It is well knov/n that the prevailing winds of the spring 
arc easterly, of the autumn westerly. In going over the siioals oi' in 
doubling Cape Cod. theie nuist be a shift of wind to gain any port 
from Plymouth to Portland. Vessels bound to them make some of 
the harbors «?f"the Vineyard sound,, and are sometimes, after sailing 
