78 Intelligence and Miscellaneous Articles, 



2. " Note on some recent openings in the Liassic and Oolitic 

 Rocks of Fawler in Oxfordshire, and on the arrangement of those 

 rocks near Charlbury." By E. A. Bather, Esq. 



The river Evenlode rises in the Lower Lias of the Yale of Moreton, 

 traverses the range of Oolites, and joins the Isis opposite Wytham 

 Mill. Lias is exposed to about three quarters of a mile below 

 Fawler, where Great Oolite is brought down by a fault ; and in the 

 Geological Survey map Lower Lias is brought down the valley to 

 within half a mile of Charlbury Railway Station. 



In this paper the author gives reasons for believing that the dis- 

 tribution of the different beds constituting the Lias in the Evenlode 

 Valley do not agree with the Geological Survey map, nor with Prof. 

 Hull's description, recent sections and borings made for clay, used in 

 brick- and pottery-making, having exposed Lower-Lias clay in a 

 brick-yard at Eawler, marlstone and Upper-Lias clay in a neigh- 

 bouring coombe, and in a long section 100 yards north of the 

 brick-yard Inferior Oolite comes in upon the Upper-Lias clay. On 

 examining the banks of the Evenlode, north of Charlbury, it was 

 found that clays referred in the Survey map to Lower Lias are 

 really Upper Liassic, being above the Marlstone, sections of which 

 are exposed near Culsham Bridge. 



It was shown how these corrections in the mapping of the ground 

 are explained by the section along the line of the Evenlode and by 

 the dips of the beds. 



XII. Intelligence and Miscellaneous Articles. 



EXPERIMENTAL PROOF OF THE LAW THAT BOTH ELECTRICITIES 

 ARE DEVELOPED AT THE SAME TIME AND IN THE SAME 

 QUANTITIES, FOR PYROELECTRICITY. BY E. DORN. 



rpVHAT both electricities are produced in equal quantities in all 

 ■*- cases of electrical excitation is a principle generally admitted, 

 though the experimental proofs are not numerous. 



It appeared to me desirable therefore to prove the above prin- 

 ciple for Pyroelectricity, particularly as here an apparently para- 

 doxical case occurs. 



If a crystal of tourmaline is warmed at one end and then rapidly 

 passed through the flame, it is first found to be almost entirely 

 unelectrical. As it cools somewhat, considerable disengagements of 

 electricity occur which are occasionally of the same kind at both ends. 



The above principle requires that the same kind of electricity occur 

 in equal quantity on the lateral faces, or in the interior of the crystal. 



A test is furnished by the principle, that a quantity of + elec- 

 tricity in the interior of a shell-shaped conductor would induce 

 — electricity on its inner, and + electricity on its outer side, 

 whatever was the distribution of the original + electricity. 



If the tourmaline, after being heated, is brought inside a con- 

 ducting but insulated hollow body, an electrometer connected with 

 the latter should show no signs of electricity as the crystal cools. 



The arrangement of the experiment was as follows : — A brass 



