VOL. XXXIV.] PHILOSOPHICAL TRANSACTIONS. 133 



1725, Dec. 17th, S^ 0"", Jupiter preceded (p Aquarii 4J-' of right ascension in 

 time, and declined from it south 1 1' 45". 



^n Extraordinary high Tide in the River Thames, observed by Capt. Tho. Jones. 

 N° 393, p. 68. 

 March the 8th, 17'25-6, the tide in the River Thames, at New Crane in 

 Shadwell, flowed 20 feet 54- inches, taken by a level, from that high-water mark, 

 to low-water the next morning, and was 4 inches higher than has been known 

 these 40 years. 



Observations on the Tides in the River Thames. By Mr. Henry de Saumarez. 

 N° 393, p. 68. 

 That the use of Mr. S.'s instrument called the marine surveyor, described in 

 N°391, may yet further appear, he here gives some experiments, made with it 

 on the River Thames, in order to determine the strength of the tides of flood 

 and ebb. Were the same to be done in the channel, and on the sea-coast of 

 Great Britain, and marked in the charts, it would be of no small advantage to 

 commerce, and a sufficient recommendation of the marine surveyor, if that 

 alone were the use of it. 



A TABLE showing the strength and gradual increase and decrease of the Tides 

 of Flood and Ebb in the River Thames, as observed in Lambeth Reach, off 

 Manchester Stairs, and in the middle of the river, with a new instrument 

 called the Marine Surveyor, on the 9th of June, 17'20; it being then full 

 moon, and consequently a spring tide. The movement of the machine 1-i 

 inches under water. 



