On the Smelting of Tin Ores in Cornwall and Devonshire. 417 
or turf four inches thick, employing 3,824 horses, and 5,843 
men, supposing it had been completed in one day. 
In order to give employment to the poor of this neighbour- 
hood, I contracted with five different persons; the whole was 
completed in August, many difficulties retarding it, from the un- 
usual quantity of rain during the summer months. On the 29th 
of May, a violent storm of wind raised the tide, and swept away 
1800 yards of material, which would have totally discouraged 
the contractors, who had no property, and could not have sus- 
tained the loss, had I not reimbursed them. I am thankful to 
say, the high tides in September and October have not made the 
slightest impression, and the whole of the work carries with it 
every appearance of stability. I apologize, sir, for the length of 
this communication ; the desire expressed in the rules of the So- 
ciety, that a detailed account should be given of works of this 
kind, must plead my excuse. Iam, sir, &c. &c. 
EpwarpD Dawson. 
The equinoctial tides in September were the highest in the | 
last twenty-four years, 
CERTIFICATES. 
. November 10, 1820. 
This is to certify, that Edward Dawson, of Aldcliffe Hall, has, 
during the summer of the present year, effectually inclosed and 
secured from the overflow of the tide, all that tract of land, near 
Lancaster, called Aldcliffe Marsh. 
R. ATKINSON, 
One of His Majesty’s Justices of the Peace for the 
County Palatine of Lancaster. 
November 10, 1820. 
I do hereby certify, that Edward Dawson, of Aldcliffe Hall, 
has, during the summer of the present year, inclosed and effec- 
tually secured from the overflow of the sea, all that tract of land, 
near Lancaster, known by the name of Aldcliffe Marsh. 
Tuomas BowEs, 
Deputy Lieutenant for the County of Lancaster. 
’ 
LXXXV. On the Smelting of Tin Ores in Cornwall and De- 
vonshire. By Joun Taytor, Esq. Treasurer of the Geo- 
logical Society*. 
As ‘I am not aware that the treatment of tin ores, or the mode 
of smelting them, has been recently described, and as the prac- 
tice is confined to a certain district, it may be acceptable to the 
Society to have some account of the processes now used in Corn- 
wall and Devon. 
* From the Transactions of the Geological Society. 
Vol. 59, No, 290, June 1822, Cat Tin 
