DUBLIN BAY DREDGING COMMITTEE. 27 



theory that they shine by reflected solar light, has been refuted by Mr. R. P. 

 Greg in the April Number of the Philosophical Magazine. 



7. It is desirable to distinguish, if possible, between ordinary shooting- 

 stars and aerolites ; Olmsted, Dr. Lawrence Smith, and Mr. Greg are strongly 

 of opinion that a distinction may frequently exist, both orbital and physical. 



8. In a paper by Prof. W. Thomson in the ' Philosophical Magazine' for 

 December 1854, " On the Mechanical Energies of the Solar System," is deve- 

 loped more fully the idea of Mr. Waterston, that the solar heat can only be 

 maintained, on any known principle, by immense numbers of meteorites 

 constantly striking the surface or atmosphere of the sun, and thus producing 

 by their enormous velocity and friction a never-failing source of heat. The 

 chief objection to this theory arises from the fact that, as far as we prac- 

 tically know anything of meteors, so far from the probability of their being 

 swallowed up in the sun goes, we see the majority of them apparently re- 

 curring without waste at periodical times, and that for a long term of years: 

 this simple circumstance goes much against the probability of Mr. Waterston's 

 and Prof Thomson's theory. 



Considering that the sun's heat, as an effect of its light, must have been 

 maintained for millions of years (as proved geologically) pretty much at its 

 present value, it is not improbable that future calculations, and a more accu- 

 rate knowledge of the phenomena exhibited by solar light, may enable us to 

 reduce considerably the supposed absolute heat of the sun, as now measured 

 by an imaginary thermometer, and thus spare us the necessity of supposing 

 that its heat is so great as to require myriads of meteors to be always rush- 

 ing into it to create a fresh supply of it. If the majority of meteors should 

 be, as they probably are, merely minute and gaseous comets, not possessing 

 a solid or stony nature, it would still more increase the chances against 

 Mr. Waterston's theory. 



9. M. Haidinger has recently published at Vienna some valuable 

 papers on the crust and external forms of meteoric stones, in relation to the 

 circumstances accompanying their fall and probable condition prior to, or at 

 the moment of, entering the earth's atmosphere. 



Report of the Committee appointed to dredge Dublin Bay. By J. R. 

 Kinahan, M.D., F.L.S., Professor of Zoology, Government School 

 of Science applied to Mining and the Arts. 



During the autumn and winter months (1859) the author made several ex- 

 cursions to the bays lo the north of Dublin, the results of which will be em- 

 bodied in the final Report. In the spring of 1860, finding that, owing to 

 circumstances beyond their control, there was no prospect of systematic 

 assistance from the other members of the Committee, the author determined 

 to fix on a district to be worked systematically, and selected the series 

 of bays between the Poolbeg Lighthouse and Bray as being the most likely 

 to yield a good return as regards number of species and variety of grounds. 

 Accordingly, since the beginning of March, a series of systematic dredgings 

 have been carried out in this district, the results of which are now communi- 

 cated. The district may be conveniently divided into three sub-districts: — 

 1st. That between the Lighthouse wall and Kingstown east pier, including 

 Kingstown Harbour. 2nd. The district between Kingstown east pier and 

 the south end of Dalkey Sound, including the whole sound. 3rd. The bay 



