372 Proceedings of the British Association. 



tions on an improved model for mountnig an equatorial instru- 

 ment, adopted by Edward J. Cooper, M. P., of Macroe Castle, 

 county Sligo. Mr Cooper bore testimony to the excellence of 

 the instrument, as also to the talent and perseverance of Mr 

 Grubb in his scientific improvements and inventions. 



11. Lieutenant Denham stated some details in I'eference to 

 the vibratory effects of rail-roads, especially over tunnels. A 

 discussion then took place between Dr Lardncr and Mr Vignol- 

 les, on the disadvantages arising from acclivities on rail-roads, 

 which appeared to the Section as over-rated by Dr Lardner. 



12. Mr Stevelly described a self-registering barometer. The 

 principle of this instrument is to suspend the mercurial cistern 

 by a mercurial hydrometer, so that it may move downwards by 

 arithmetical distances, for equal additions to its weight, and vice 

 versa. Hence, if a scale be fixed beside it, an index carried by 

 the cistern as it falls and rises will mark the corresponding po- 

 sitions. 



Section B. — Geology and Geography. 



President. — Mr Griffith. 



Vice-Presidents.— '^Ir Muhchisoj!. Professor Sedgwick. 

 Secretaries. — Captain Portlock. Thomas Jameson^ Torrie, Esq. 



Committee G. B. Greenough, Esq. James Bryce, Esq. jVfajor Gierke. 'W'il- 



liam Smith, Esq. John Taylor, Esq. Sir G. Mackenzie. Dr Traill. 

 Henrj' Woolcombe, Esq. JI. Agassiz. AMlliam Nicol, Esq. Ilev. W. 

 Turner. Sir A. Crichton. Sir John Franklin. Sir John lloss. Captain 

 Sabine. Lord Cole. Colonel Colby. Thomas Larcom, Esq. E. Tay- 

 lor, Esq. J. Taylor jun. Esq. 11. Fox, Escj. Elios Hall, Esq. .Tames 

 Macadam, Esq. l{ev. Sydney Smith. Captain James Ross, R. N. Dr 

 Scoular. A. Nolan, Esq. Viscount Adare. Lieutenant Stotherd. 

 Captain Denham, R. N. Dr A\^est. Thomas Botfield, Esq. J. Menteath, 

 Esq. Colonel H. Montgomery. James Smith, Esq. Lieut. Bcides. 

 Joshua Trimmer, Esq. "Williamson Peile, Esq. C. Konig, Esq. Decimus 

 Burton, Esq. J. Preswick, Esq. ]M. C. F. de Montaleuibert. M. ICd. 

 de Verneuil. Samuel Turner, Esq. Sir James Douglas. 



Monday, August 10. — 1. Mr Griffith presented his Geologi- 

 cal Map of Ireland, the result of many years" research and la- 

 bour ; and pointed out the difficulties which at present attended 

 the delineation of the boundaries of the formations consequent 

 on the imperfections of the existing map?. He said he of course 

 excepted the maps published by the Ordnance survey, than 



