VOL. XLI.J PHILOSOPHICAL TRANSACTIONS. 457 



the concave valve, there is a sort of cistern, containing the water which is 

 greedily drawn in, closed with a thin shelly plate, and from the hinge generally 

 equalling the whole bed of the animal ; and I have learned by experience, that 

 this cistern, when it is distinct from the hard shell, is apt to deceive the un- 

 skilful : for it has happened more than once, that some have pronounced the 

 cavity covered with a transparent plate in fossil oysters, to be the figure of the 

 oyster rudely inscribed on either shell. 



Perhaps such a shell of Mount Nicosia might impose upon Le Bruyn, " That 

 the oyster has imprinted its shape on the shell," when he boldly appeals to his 

 figure, " as may be seen in the figure :" whereas even his figure, considered 

 attentively, shows nothing but the mere shell, representing only an imaginary 

 shape of the oyster. I could prove this assertion by many schemes. 



Observations of the Planet Mars, viade at Berlin, in the Autumn of 1736. By 

 Christ. Kirch, Astronomer of the Royal Academy there. N° 459, ?• 573- 



Some observations of that planet, as to its places and situations, with res- 

 pect to the sun and fixed stars, &c. 



A Collection of the Observations of the remarkable Red Lights seen in the Air on 

 Dec. 5, or iQth N. S. 1737, sent from different Places to the Royal Society. 

 N° 459, P- 583. 



1. As observed at Naples by the Prince of Cassano, F.R.S. p. 583. — Dec. l6, 

 1737, N. s. in the evening, the sun being about 25 degrees below the horizon, 

 a light was observed in the north, as if the air was on fire, and flashing; the 

 intenseness of which gradually increasing, at the 3d hour of the night it spread 

 much westward. Its greatest height was about 65°; for it occupied the whole 

 extent of both the Bears and the polar star; yet at the sides it was not so high; 

 for in some places near the north it rose only to 50°, and it gradually diminished, 

 so as to become insensible at the true horizon. 



The abovementioned light at its extremities was unequally jagged, and scat- 

 tered, and followed the course of the westerly wind; so that for a few hours it 

 spread considerably wider, yet without ever reaching the zenith. About the 

 6th hour of the night the intenseness of the colour disappeared : some small 

 traces of the inflammation still remaining towards the north-east and the west, 

 which were all vanished at 7-3-'' of the night. 



The inflamed matter, in the greatest part of its extent, gave a free passage 

 to the rays of the stars, even of the 3d and 4th magnitude, situate behind it. 

 About the 4th hour of the night, a very regular arch, of a parabolic figure, 



VOL. VIII. 3 N 



