1817.] On Canal Levels. 179 
4. The rise of the Severn from Stourport to Shrewsbury, to 
eonnect the Ellesmere, the Montgomeryshire, and the Chester 
» Canals. 
5. The difference of level between the Lancaster, and the Leeds 
and Liverpool canals, where they intersect each other, which seems 
to be about two miles north of West Houghton. 
6. The fall of the River Aire from Leeds to the sea. 
7. The fall of the Thames from Brentford to the sea. 
8. The fall of the Severn from the sill of the canal lock at 
Worcester, to the Avon at Tewkesbury, thence to Gloucester, and 
from Gloucester to the sea. 
9. The fall of the Avon from the Kennet and Avon Canal lock 
at Bath to Bristol! Bridge, and thence to the Severn. 
10. The fall of the River Nen where it joins a branch of the 
Grand Junction Canal at Northampton, to Peterborough, and from 
thence to the sea. 
11. If in the reply to the 6th, 7th, Sth, 9th, and 10th inquiries, 
a reference were made to fixed points, contiguous to those estimated 
to be the high and low water marks, it would afford as great an 
approximation to accuracy as circumstances will admit; and pro- 
bably the barometrical admeasurement, conducted with all the 
proper precautions, may be the most easily adopted in most of these 
cases. 
12. Mr. Rennie, ia a plan surveyed under his direction by Mr. 
Crossley in 1791, states the lockage of the Rochdale Canal to be on 
the east side 275 feet, and on the west 4381 feet; and Mr. Sut- 
cliffe, in his Treatise on Canals, says, rise on the east side 358 
feet, fall on the west 521 feet. Does this difference arise from the 
lockage of the canal having been increased, to avoid a tunnel or 
deep cutting at the summit? 
Iam, Sir, yours very respectfully, 
SamMuEL GALTON, 
Reference to the Chart of a Synoptic View of the Levels of 18 
Canals, in Reference to the Summit of the Birmingham Canal : 
to which is added the Authority of each Survey. 
RISE, FALL, 
Feet | Inches} Feet | Inches 
I. The Staffordshire and Worcestershire Canal 
commences in the River Severn at Stourport, unites 
with the Stourbridge Canal at Stourton, with the 
Birmingham Canal at Autherley, and falls into the 
Grand Trunk Canal at Heywood, Staffordshire. 
Rise from Stourport to Autherley ............ 294 8 
Fall from thence to Heywood ................ 100 6 
TotalasWssccc 294 8 100 6 
(From Cary’s Canal Plans, assisted by a statement 
from the Company’s clerk.) } 
M 2 
