66 Royal Society. 



sity, the (lepolari/ation was complete^ and the jelly had ac- 

 quired the property of depolarizing light in every direction, like 

 other objects before operated on by the author. 



A letter from Dr. Storer was read, describing the nature and 

 circumstances of a spring of fresh water discovered in the har- 

 bour of Bridlington, Yorkshire, a few years ago, when boring 

 in order to ascertain the practicabilitv of making some improve- 

 ments in the harbour. The tide here flows to the height of 

 fourteen feet, and the boring was commenced near the low- 

 water mark ; the soil is a stiff blue clay, and when the auger 

 had passed through about twenty-eight feet, it struck on a very 

 hard rock, and the operation was discontinued. At first there 

 was no appearance of water ; but after a few hours fine fresh 

 water !>egan to rise, and rose so rapidly that it flowed over the 

 side of the works raised for the experiment. As Bridlington 

 was not well supplied uith water, a tube was inserted in the 

 bore, the parts around it covered over, and the conveyance 

 made for the \^ater to nui into reservoirs when the tide flowed. 

 This spring has now continued to flow with the tide some years, 

 and supply the town with good fresh water ; when the tide ebbs 

 it ceases to flow, and as the tide rises so does the water in the 

 spring. In summer many of the wells in the neighbourhood are 

 dry, but this remains permanent. When great floods occur in 

 consecjuence of the rains at the end of autumn, the water of 

 this well rises higlier ; which is the only change that it experi- 

 ences. The explanation of this a])pcarance offered by Mr. 

 Mihie, the arcliitect of the works, is, that the whole bay ex- 

 tending to a considerable distance is covered with the same stra- 

 tum of blue clay which ultimately terminates in the sea on the 

 rock which runs under the spring, and that the rise or flow of 

 the water in the well is occasioned by the superior gravity and 

 pressure of the tide, acting like as the two arms of a syphon 

 charged with two fluids of different specific gravities. Dr. 

 Storer admits this explanation as generally satisfactory ; but ob- 

 serves that, according to this theory, the well instead of flowing 

 higher during floods should not rise so high, as there must be a 

 greater quantity of fresh to resist the action of the salt water. 



The Doctor's objection seems founded on the notion that the 

 increased quantity of fresh water should also increase its spe- 

 cific gravity ; but it is the volume only which is increased, and 

 hence an increased flow from the well. 



Jan. 20. Part of a paper by Mr. Cooke was read, proposing 

 some methods of improving marine charts, and facilitating their 

 general use. It also contained some suggestions for taking 

 angles from light-houses with the pole star, and coasting at 

 night, &:c. many of which necessity had long ago anticipated. 



He 



