February 6tli, njij.] PROCEEDINGS. xvii. 



Ordinary Meeting, February 6th, 191 7. 



The President, Professor Sydney J. Hickson, M.A., D.Sc., 

 F.R.S., in the Chair. 



Mr. C. L. Barnes, M.A., made a short communication on 

 " GalVanit," a preparation 'brought out some years 'ago Tor 

 depositing silver, nickel, or cadmium on a surface of copper 

 or br;ass. The active ingredients were powdered magnesium 

 and a salt oi the metal to be deposited, but the method soon 

 fell into disuse, through the layer not proving sufficiently adhe- 

 rent. A tin of the silver mixture w'as placed in the Society's 

 keeping. 



Professor BOYD Dawkins conveyed to the Society his deep 

 regret that Oiwing to illness, he was unable to be present to re^d 

 his paper Oiu "The Place of the Manchester Museum in 

 the General Scheme of Education." 



Mr. T. A. Coward, F.Z.S., F.E.S., then took the chair, and 

 the President made a coimmunication on " Polytrema and 

 allied foraminifera," and e.xhibited some specimens and a series 

 of lantern slides to show their structure. 



Ordinary Meeting, February 20th, 191 7. 



The President, Professor SYDNEY J. HiCKSON, M.A., D.Sc, 

 "F.R.S., in the Chair. 



Dr. HiCKLiNG referred to. the very large group of sun-spots 

 which has recently been visible, and so.me discussion took place 

 on this subject. 



Dr. W. Makower, M.A., then read a paper on " The 

 Photographic action of a Rays." 



Djr. Makoiwer stated that although the discovery oT the 

 radio-activity of uranium was. made by the photographic action 

 of uranium salts as long ago a|s 1896, the nature of this effect 

 was noit studied in detail for many years. The first importanit 

 investigation of the photographic action of a pai'ticles was made 

 in 1 910 by Kinoshita, who succeeded in showing that whenever 

 an a particle strikes a grain of silver hahde in a photographic 

 plate, that grain is subsequently capable of photographic de- 

 ve,lopment; moreover, this was true throughout the range of the 

 a particle. Later it was isho.wn by Reinganum and others that 

 when a particles are projected tangentially tO' a photographic 

 plate after development the film shows definite trails of grains 

 of silver hahde, which can readily be distinguished under the 

 microiscope. These trails are produced by the impact of the 



