336 Proceedings and List of Papers read. 



was directly focussed on the sensitive film without the interposition of 

 the prism. The photographs show a straight image of the slit followed 

 by a number of curved bands extending from both poles into the 

 spark gap. 



The straight image we consider to be the initial discharge through 

 air creating sufficient heat to fill the space with vapour through which 

 the oscillating discharges may then pass. Our experiments point to 

 the fact that the periodic time was rather too small in our experiments 

 to give the t best results. The metallic molecule before it has had time 

 to reach through a sufficient distance was possibly affected in its 

 motion by the subsequent oscillation. We hope to remedy this defect 

 by introducing still higher capacities than those used. Our experi- 

 ments allow us to give the following approximate numerical data. 

 The air rendered luminous by the first discharge remains luminous for 

 a time of about 5 x 10~ 7 second, the metallic vapours then begin to 

 diffuse and reach the centre of the spark (the gap being 1 cm. long) in 

 a time which in the case of cadmium was about 6 x 10~ 6 second. The 

 periodic time of the oscillations with our six jars and a circuit possess- 

 ing as little self-induction as possible was about 2 x 10~ 6 second. The 

 metallic vapours remain luminous in the centre of the spark for a 

 longer period than near the poles, the Duration of the time during 

 which some luminosity can be traced with a discharge from six Leyden 

 jars is about 1*5 x 10~ 5 second. 



February 9, 1899. 

 The LOED LISTEE, F.E.C.S., D.C.L., President, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The following Papers were read : 



I. " On the Eeflection of Cathode Eays." By A. A. C. SWINTON. 

 Communicated by LORD KELVIN, F.E.S. 



II. " On the Eecovery of Iron from Overstrain." By JAMES Mum, 

 B.Sc. Communicated by Professor EWING, F.E.S. 



III. " A Soil Bacillus of the Type of De Bary's B. megatherium''' By 

 W. C. STURGIS, M.A., Ph.D. Communicated by Professor 

 MARSHALL WARD, F.E.S. 



