Intelligence and Miscellaneous Articles. 77 



logical evidence combined to establish the position which he assumed 

 in his introduction — that the Great Oolite limestone of North- 

 ampton was identical with what he considered was Great Oolite 

 at Stamford, and that the " Lincolnshire limestone" was a distinct 

 formation, and a member of the Inferior Oolite series. 



He had confidence that he had shown that the series of beds in 

 the north-eastern portion of the northern division of Northampton- 

 shire comprised all the beds between the Oxford Clay and Upper 

 Lias inclusive, including the Lincolnshire limestone — and that those 

 of the south-western portion comprised the same sequence, excluding 

 the Lincolnshire limestone. 



He considered that the Great Oolite Clay represented the Forest 

 Marble and the Bradford Clay of the West of England ; that the 

 Great Oolite limestone was nearly equivalent to the Great Oolite of 

 Bath and the Cotteswolds, and to the upper beds of Minchin- 

 hampton ; that the Upper Estuarine might be nearly identical with 

 the Upper Plant Shale of Yorkshire, but more certainly with the 

 Stonesfield slate of Oxfordshire; that the Lincolnshire limestone 

 was nearly synchronous with the grey limestone of Yorkshire (In- 

 ferior Oolite), and probably with the lower portion of the Am. 

 Humphriesianus zone of the west of England, but extending a little 

 below this zone ; that the Lower Estuarine answered to the Lower 

 Plant Shale of Yorkshire, but had no representative in the west ; 

 that the upper portion of the ferruginous beds of the Northampton 

 Sand was nearly upon the same horizon as the Glaizedale and Dogger 

 beds of Yorkshire and the Am. Murchisonce zone of the west ; and 

 that the lower portion of the Northampton sand was represented by 

 the Am. opalinus zone and the Midford Sand. 



XI. Intelligence and Miscellaneous Articles, 



ON SOME PHENOMENA OF ILLUMINATION. BY A. LALLEMAND. 



A LL the effects of illumination observed in diaphanous bodies 

 ■^ traversed by the light of the sun, either natural or polarized, 

 are readily explained if it be admitted that the vibratory motion of 

 the aether in penetrating the transparent medium, encounters a re- 

 sistance in virtue of which the vibrations are propagated laterally 

 in such a manner that along any direction oblique to the incident 

 ray the motion of the aethereal particle represents the projection 

 of that of the aether on its passage from the luminous pencil, and 

 if, on the other hand, it be also admitted that the molecules of the 

 medium, absorbing a portion of the vis viva of the aether, vibrate in 

 their turn and propagate in the aethereal fluid the complex vibra- 

 tions which constitute natural light. The illumination therefore 

 results from two effects superposed ; and the light emanating from 

 it is formed of two sorts of rays : the one sort, always of the same 

 colour as the incident rays, are polarized either partially or com- 

 pletely, according as the incident pencil is neutral or polarized ; the 

 others, the refrangibility of which is often inferior to that of the 

 exciting rays, have the properties of natural light, and determine a 

 general property of bodies which has been called fluorescence. In 



