Things not generally Known. 



large tusk without having been flattened, as they are found by 

 the ivory-turner. 



The explanation is as follows : A musket-ball aimed at the head of 

 an elephant may penetrate the thin bony socket and the thinner ivory 

 parietes of the wide conical pulp-cavity occupying the inserted base of 

 the tusk ; if the projectile force be there spent, the ball will gravitate 

 to the opposite and lower side of the pulp-cavity. The pulp becomes 

 inflamed, irregular calcification ensues, and osteo-dentine is formed 

 around the ball. The pulp then resumes its healthy state and functions, 

 and coats the osteo-dentine enclosing the ball, together with the root of 

 the conical cavity into which the mass projects, with layers of normal 

 ivoiy. The hole formed by the ball is soon replaced, and filled up by 

 osteo-dentine, and coated with cement. Meanwhile, by the continued 

 progress of growth, the enclosed ball is pushed forward to the middle of 

 the solid tusk ; or if the elephant be young, the ball may be carried 

 forward by growth and wear of the tusk until its base has become the 

 apex, and become finally exposed and discharged by the continual abra- 

 sion to which the apex of the tusk is subjected. Professor Owen. 



NATURE OF THE SUN. 



To the article at pp. 59-60 should be added the result ob- 

 tained by Dr. Woods of Parsonstown, and communicated to the 

 Philosophical Magazine for July 1854. Dr. Woods, from photo- 

 graphic experiment, has no doubt that the light from the centre 

 of flame acts more energetically than that from the edge on a 

 surface capable of receiving its impression ; and that light from 

 a luminous solid body acts equally powerfully from its centre 

 or its edges : wherefore Dr. Woods concludes that, as the sun 

 aifects a sensitive plate similarly with flame, it is probable its 

 light-producing portion is of a similar nature. 



Note to " Is THE HEAT OF THE SUN DECREASING ?" at page 65. 

 Dr. Vaughan of Cincinnati has stated to the British Association : 

 t( From a comparison of the relative intensity of solar, lunar, and arti- 

 ficial light, as determined by Euler and Wollaston, it appears that the 

 rays of the sun have an illuminating power equal to that ot 14,000 can- 

 dles at a distance of one foot, or of 3500, 000000, 000000, OuOOOO, 000000 

 candles at a distance of 95,000,000 miles. It follows that the amount 

 of light which flows from the solar orb could be scarcely produced by 

 the daily combustion of 200 globes of tallow, each equal to the earth in 

 magnitude. A sphere of combustible matter much larger than the sun 

 itself should be consumed every ten years in maintaining its wonderful 

 brilliancy; and its atmosphere, if pure oxygen, would be expended be- 

 fore a few days in supporting so great a conflagration. An illumination 

 on so vast a scale coul 1 be kept up only by the inexhaustible magazine 

 of ether disseminated through space, and ever ready to manifest its lu- 

 ciferous properties on large spheres, whose attraction renders it suffi- 

 ciently dense for the play of chemical affinity. Accordingly suns de- 

 rive the power of shedding perpetual light, not from their chemical 

 constitution, but from their immense mass and their superior attractive 

 power." 



