Professor Owen on British Fossil Beptitet, 65 



A convenient metliod of executingthis is to have two stretch- 

 ing frames made perfectly level, to join them together at the 

 bottom by a hinge of thin leather, to cover the faces in con- 

 tact with paper, or linen, and to adapt the groove of the box 

 to receive them (as well as the ordinary single frames), and 

 to admit of the second frame being moved backward and 

 forward at the top. This motion may be communicated by 

 a thin lever passing through the bottom of the box, close to 

 the side next to the exhibitor, immediately behind the second 

 frame. The effect thus produced is, however, not a correct re- 

 presentation of fog. 



A more simple and easy method of producing a representa- 

 tion of fog, w^hich is correct, is to use an ordinary single frame 

 only, to paint the objects intended not to be affected by the 

 fog on the front of the frame (painting behind them also if 

 necessary to produce sufficient opacity), and the rest of the 

 scene on the back of it, to admit light in front, and gradually 

 either to admit light behind, by which the parts of the scene 

 painted on the back will appear to emerge from the fog, or 

 to exchide that light, by which they will appear to become 

 involved in the fog. 



a Tait. 



Edinburgh, Wth April 1842. 



On British Fossil Beptiles. By Professor Owen. 



A RETROSPECTIVE glaucc at the catalogue of reptiles which 

 formerly existed on that portion of the earth's surface consti- 

 tuting the present small island of Britain, and which are now 

 extinct, must call forth such novel and surprising reflections 

 on the dealings of Providence with the animated beings of 

 this planet, as may well lead, in the first place, to a question- 

 ing of the truth of the affirmations with which the present 

 summary commences. Did the numerous, strange, and gigan- 

 tic representatives of the several orders of reptiles actually at 

 any time live and move, and propagate their kind in the loca- 

 lities where their bones are now so abundantly found ? Are 

 not these bones the relics rather of antediluvian creatures, 



VOL. XXXIII. NO. LXV. JVLY 1842. ■ 



