374 Royal Institution : — Prof. Tyndall on the Acoustic 



emanated from the uninviting work of examining in detail the 

 stellar proper motions. 



On the coiniug transits of Yenus we have but little, if any thing, 

 to say. To us this portion of the volume appears to assume too 

 much of personality ; and we therefore leave the matter for its final 

 settlement in December next. The plates, however, illustrating it 

 may be consulted with great advantage. 



Elementary Astronomy, or Notes and Questions on the Stars and Solar 

 System for the use of Schools. By C. C. Reeks. London : Van 

 Voorst. 1873. 



Although this little book of fifty pages is intended for young 

 people and even children, it contains information which in our 

 opinion many " children of a larger growth " ought to become 

 acquainted with. The author has given in it an interesting 

 resume of all the salient points of the physical characteristics of the 

 stars, nebulas, planets, comets, meteors, and especially of the sun, 

 divested of matter which too often tends to "make a book" with- 

 out really illustrating the subject in hand. Each paragraph brings 

 before the reader in condensed language an astronomical (and, as 

 regards the earth, a geological) fact worth remembering. It is the 

 simplicity and perspicuous brevity which characterizes this epitome 

 of astronomy that has induced us to notice it in our pages as a work 

 that should find a corner in every library. 



XLVIII. Proceedings of Learned Societies. 



ROYAL INSTITUTION OF GREAT BRITAIN. 



Jan. 16, "/^N the Acoustic Transparency and Opacity of the Atmo- 

 1874. v*J sphere." By Professor Tyndall, D.C.L.,LL.D.,F.R.S. 



This discourse embraced the scientific results of an inquiry on 

 fog-signals, undertaken at the instance of the Elder Brethren of 

 the Trinity House, and communicated, with their friendly concur- 

 rence, to the Royal Society and the Royal Institution. 



The investigation was begun on the 19th of May, 1873, and con- 

 tinued till the 4th of July. It was resumed on the 8th of October, 

 and continued to the end of November. It also includes observa- 

 tions made during the dense fog which enveloped London on De- 

 cember 9 and the succeeding days. 



Gongs and bells were excluded from this investigation, in conse- 

 quence of their proved inferiority to other instruments of signalling. 

 The experiments were made with trumpets blown by powerfully 

 compressed air, with steam-whistles, guns, and a steam syren asso- 

 ciated with a trumpet 16 feet long. 



Daboll's horn, or trumpet, had been highly spoken of by writers 

 on fog-signals. A third-order apparatus of the kind had been 

 reported as sending its sound to a distance of from 7 to 9 miles 

 against the wind, and to a distance of 12 to 14 miles with the wind. 



