( (58 ) 
HI. An Extraordijiary high Tide in the ^Ver 
Thames ohjervd by Capt. T h o. J O N E s- 
M arch the 8th, 1725.6, The Tuie in the 
River Thames, at Hew Crane in Sbadwell, 
flow’d twenty Foot, five Inches and a half, taken by 
a Level, from that High-water Mark, to Low-water 
the next Morning, and was four Inches higher than 
has been known thefe fourty Years, 
IV. Obferyations ujwn the Tides in the ^iyer 
Thames^ by Mr. Henry de Saumarez. 
T H a T the Ufe of my Inflrument call’d the 
Marme Surveyor may yet farther appear,! fliall 
here give fome Experiments I made with it on the 
River Thames^ in order to determine the Strength of 
the Tides of Flood and Ebb.WcvQ the fame to be done 
in the Channel, and on the Sea Coafl of Great Britain, 
and mark’d in our Charts, I am humbly of Opinion, 
it would be of no fmall advantage to our Commerce, 
and of confequence a fufficient Recommendation of 
Fne. Marine Surveyor, if that alone were the Ufe of it. 
I am induced the rather to be of this Opinion, in 
regard I am not infenfible of the Dangers on the 
Cafquets, in the Race of Alderney, 6{c. where rapid 
Tides and Currents have occafioned but too many 
to mourn the Lofs of Friends and Fortunes : As I 
dwell in the Neighbourhood of thefe Dangers, I have 
(in manifeff hazard of my Life) furvey’d and taken 
corred Draughts not only of them, but of the If- 
lands of Guer?jfey, Sarck, 6cc, And as 1 perfuade my 
felf they are as corred, as any Thing that has hither- 
to appear’d of this kind, it is iny intent to publifli 
them for the Good of the Publick. 
Vid, Philof. Tvanfad. No. 391. 
