I860.] Professor Tyndall,on the Electric Discharge. 169 



Petermann, A. Esq. (the SiiVor)— Mittheiliingen auf dem Gesammtgebiete des 



Geographic. 1859. Heft 10. 4to. Gotha, 1859. 

 Photographic Society— J omna.\, No. 91. 8vo. 1859. 

 Boi/at Socielif o/' Zo/ir/on— Transactions, Vol. CXLIX. Part 1. 4to. 1859. 



Places of 5345 Stars, observed from 1828 to 1854, at the Armagh Observatory. 



By the Rev. T. R. Robinson. 8vo. 1859. 

 JVuslees of the British Museum — List of Books of Reference in the Reading-room. 



8vo. 1859. 

 Catalogue of Orthopterous Insects. Part I. with Plates. By J. O. Westwood. 



4to. 1859. 

 Catalogue of the Coleopterous Insects in Madeira. By T. V. Wollaston, 8vo. 



1857. 

 Catalogue of HispidsG. By J. S. Baly. 8vo. 1858. 



Catalogue of Batrachia Salientia. By Dr. A. Gunther. Plates. 8vo. 1858. 

 Catalogue of Apodal Fish. By Dr. Kaup. Plates. 8vo. 1856. 

 Guide to the Systematic Distribution of MoUusca. By Dr. J. E. Gray. 8vo. 



1857. 

 Catalogue of Mammalia and Birds of New Guinea. By J. E. and G. R. Gray. 



8vo. 1859. 

 List of Lepidopterous Insects. By F. Walker. Parts 9 to 18. 12mo. 1856-9. 

 Catalogue of Hymenopterous Insects. By F. Smith. Parts 5, 6, 7. 12mo. 



1857-9. 

 List of Homopterous Insects. By F. Walker. Supplement. 12mo. 1858. 

 Catalogue of Coleopterous Insects. Part 9. By C. Boheman. 12mo. 1859. 

 Catalogue of Neuropterous Insects. By Dr. Hagen. Parti. 12mo. 1858. 

 Catalogue of British Fossorial Hymenoptera, Formicidse, and Vespidse. By F. 



Smith. 12mo. 1858. 

 Catalogue of Colubrine Snakes. By Dr. A. Gunther. 12mo. 1858. 

 Catalogue of Birds. By G. R. Gray. Part 3; Sect. 2. 12mo. 1859. 

 Catalogue of Mazatlan Shells. By P. Carpenter. 12mo. 1857. 

 Catalogue of AuriculidsD, Proserpinidae, and Truncatellidse. By Dr. L. Pfeiffer. 



12mo. 1857. 

 United Service Institution — Journal, No. 10. 8vo. 1859. 

 Vereins zur Beforderung des Gewerhfleisses in Preussen — July und Aug. 1859. 4to. 



1860. 



WEEKLY EVENING MEETING', 



Friday, January 20, 1860. 



Sir Benjamin Collins Brodie, Bart. President of the Royal Society, 

 Vice-President R.I. in the Chair. 



John Tyndall, Esq. F.R.S. 



PBOFESSOB OF NATURAL PHILOSOPHY IN THE BOTAL INSTITUTIOK. 



On the Influence of Magnetic Force on the Electric Discharge, 



The intention of tlie speaker was to bring before the meeting a series of 

 experiments illustrative of the constitution of the electric discharge and 



