366 Scientific Intelligence. 



ascribed by Encke to the resistance of an ether diffused in space, which 

 produces a diminution both in the periodic times and in the eccentricities. 

 M. O. F. Mosotti, of the Italian Society, has endeavoured to calculate the 

 resistance which a comet may experience from that cause, and by assum- 

 ing for it a particular law of density, and taking into account the continual 

 changes in the figure and volume of the comet as it approaches to or re- 

 cedes from the sun, he arrives at the conclusion, " that on the hypothesis 

 adopted, the comet may have experienced from an ether a resistance such 

 as is required to make the calculus accord with observations, though the 

 planets have not yet manifested the least effect of the existence of that 

 ether. As nothing opposes the probability that the hypotheses which we 

 have made, or some others analogous to them, are really correct ; and as, 

 moreover, the effect of the acceleration of the mean motion of this comet 

 supports the opinion of the existence of an ether, a greater degree of credit 

 will, no doubt, be assigned to the hypothesis. If the comet which we ex- 

 pect eleven years hence (in 1835) display corresponding effects, we shall 

 then be authorized to regard the diffusion of an ether, in celestial space, as 

 an admissible fact." — Mem. Astron. Soc. vol. ii. part i. p. 62. 



9. Change upon the figure of Saturn when emerging from the Moon's 

 dark limb. — Mr R. Cornfield, with a Gregorian reflector, power 350, and 

 Mr J. Wallis with a Newtonian reflector, power 160, when observing 

 the emersion of Saturn, on the 30th October, noticed that the part of the 

 ring which last emerged was rendered sensibly more obtuse, and at the 

 instant after separation it approximated to a rectilineal boundary. When 

 the eastern limb of the globe of Saturn emerged, Mr Cornfield observed u 

 similar effect upon it. 



ACOUSTICS. 



10. Deaf ness arising from the Eustachian Tube. — The Academy of Sciences, 

 at their public sitting of the 5th June, have awarded a sum of two thousand 

 francs to M. Deleau, author of different memoirs, for having brought to 

 perfection the catheterism of the Eustachian tube, and for having cured, 

 by this means, some individuals affected with that rare cause of deafness. 



11. Great distance at which Sounds are Heard. — At Port Bowen Lieu- 

 tenant Foster kept up a conversation with his assistant, at a distance of 

 6696 feet, or about one statute mile and two-tenths. — Captain Parry's 

 Third Voyage. 



OPTICS. 



12. Phosphorescence of the Glow-Worm, of the Fire-Fly, and the Lam- 

 pyris Noctiluca. — The following is the substance of a paper on this sub- 

 ject by Dr Todd, in the last number of the Institution Journal. 



The light of the femule glow-worm is of a light topaz colour, witli 

 rather a tinge of green. The hour upon a watch may be observed by it. 

 The light of the male is of the same colour. It is confined to two very 

 small round spots, and is seldom emitted spontaneously, excepting in cer- 

 tain sexual relations. The light, however, appears instantaneously by the 

 least irritation or pain. 



