1853.] OF THE ROYAL INSTITUTION. 319 
division of the Eocenes. As these Maltese beds are unconformable, 
and evidently long subsequent to the deposition of the great num- 
muletic formation, we are enabled to assign an approximate limit 
to the estimate of the latest age of that important series. From 
well marked analogies we get at a probable date even for the Aus- 
tralian tertiaries. Thus the deciphering of the true structure of a 
small portion of the British Islands can throw fresh light upon the 
conformation of vast and far-apart regions. 
The peculiar undulatory contour of the surface of the fluvio-marine 
portion of the Isle of Wight is due to the gentle rolling of these 
beds in two directions, one parallel with the strata of the chalk ridge, 
and the other at right angles to it. The valleys and hills running 
northwards to the sea depend upon the synclinal and anteclinal 
curves of the latter system of rolls, a fact hitherto unnoticed, and 
the non-recognition of which has probably been one cause of the 
erroneous interpretation of the structure of the Isle of Wight, 
hitherto received. The truncations of these curves along the coast 
of the Solent exhibit at intervals beautiful and much neglected 
sections, well worthy of careful study. There is one of these 
sections near Osborne. Her Majesty’s residence stands upon a 
geological formation hitherto unrecognized in Britain. Near West 
Cowes there are several fine sections along the shore. The total 
thickness of unclassified strata in the Isle of Wight is four hundred 
feet, if not more, and within this range are at least two distinct sets 
of organic remains. The fluvio-marine beds in all, including the 
Headon series, are very nearly 600 feet thick. 
[E. F.] 
WEEKLY EVENING MEBRTING, 
Friday, May 20. 
Sir Joun P. Botteav, Bart., F.R.S., Vice-President, 
in the Chair. 
Dr. E. Franxuanp, F.C.S. 
Observations, economical and sanatory, on the employment of Chemical 
Light for artificial Ilumination. 
THERE are two principal sources of artificial light, viz. electricity 
and the chemical force ; the latter, however, has been, and still is, 
the only practical source of all artificial light. Although light can 
be thus obtained by the chemical action of substances belonging 
to all three kingdoms, yet closer observation demonstrates that the 
