976 



SCIENCE. 



[N. S. Vol. XVII. No. 442. 



ROYAL SOCIETY CONVERSAZIONE* 

 The first of the two Royal Society con- 

 versaziones has been held at the society's 

 rooms in Burlington House. There was, 

 as usual, a large attendance, the visitors 

 being received by the president. Sir Wil- 

 liam Huggins. 



The exhibits seemed to be more numerous 

 than the average, and, on the whole, each 

 had a wider range than last year. Exhibits 

 in the departments of physics and chem- 

 istry predominated, electricity and its ap- 

 plications being prominent. Naturally, 

 special interest was manifested in the new 

 coherer as applied to wireless telegraphy, 

 sliown by Sir Oliver Lodge and Dr. Alex- 

 ander Muirhead. The coherer consists of 

 a steel wheel which rotates so that its edge 

 touches a pool of mercury through a film 

 of oil, the decoherence being automatic. 

 A fraction of a volt is used in the detect- 

 ing circuit, which works a siphon recorder 

 as the receiving instrument. The sending 

 post of the station was also shown. It 

 ought to be noted that some years ago, at 

 a Royal Society soiree, Sir Oliver Lodge 

 exhibited an arrangement for wireless 

 telegraphy, of which this may be regarded 

 as the parent stage. Sir Oliver Lodge is 

 devoting himself rather to the perfection 

 of his arrangement than to. the attainment 

 for the present of long distances. Another 

 exhibit which naturally attracted much at- 

 tention was that by Sir William Crookes, 

 illustrative of the properties of the emana- 

 tions of radium. There were autoradio- 

 graphs, photographs of radium emanations, 

 luminous effects of radium emanations, and 

 an ingenious little instrument which Sir 

 William Crookes calls a spinthariscope, in- 

 tended as a convenient contrivance to show 

 the scintillations of a piece of radium ni- 

 trate. A solution of radium on a small 

 plate formed a permanent lamp, which 

 might really be of practical use. 

 * From the London Times. 



Included among other exhibits of an 

 electrical character may be mentioned the 

 Rev. P. J. Jervis-Smith 's high-pressure 

 spark-gap, consisting of a thick glass globe 

 furnished with two platinum-faced balls, 

 adjustable for distance, used in connection 

 with an inductor of the Tesla type, and 

 also in connection with a radiator of 

 Hertzian waves. Mr. A. Williams showed 

 some brilliant experiments to illustrate a 

 method, by means of a shunt, of control- 

 ling and regulating spark discharges, so 

 as to make them more regular and more 

 under control for therapeutic and wireless 

 telegraphy purposes. 



Dr. W. Ramsden's experiments, to 

 demonstrate the presence and spontaneous 

 formation of solid membranes upon the 

 free surfaces of certain solutions, were 

 striking, and some of the results, including 

 micro-photographs and microscopic speci- 

 mens, were very beautiful. Mr. Joseph 

 Goold's diagrams, illustrating the order 

 and origin of the musical scales, showing 

 that the system of sounds commonly em- 

 ployed in written music is dual through- 

 out, were remarkable. Mr. A. E. Tutton 

 exhibited an elaborate arrangement which 

 he calls an elasmometer, for the determina- 

 tion of the elasticity of solid substances, 

 particularly crystals, which can not be ob- 

 tained in very large pieces. Mr. W. Wat- 

 son's light mirrors suitable for galvanom- 

 eters are made of fused silica, the reflect- 

 ing surface consisting of a film of platinum. 

 An experiment by Mr. 0. W. Richardson 

 illustrated the conductivity imparted to a 

 vacuum by hot carbon. Dr. Common ex- 

 hibited a coUimating gunsight for use by 

 day and night, consisting of a lens mounted 

 in a tube fixed at the top or side of the 

 gun, with a fiducial mark at its focus, the 

 mark being a black spot for day work or 

 a small luminous red spot for night work. 

 Dr. Common also showed an optical sight 



