Jloyal Institution. 381 



also intercepted the magnetic influence j and in a ratio corresponding 

 with that in which different bodies in rotation are affected by or affect 

 a magnet. The results of these and other modes of investigation were 

 fully described. 



Feb. 18. Mr. Faraday gave an experimental account of the new 

 substance discovered by M. Dumas, and called by him oxamidi or 

 oxalamidi. See our present volume, p. 67. 



Feb. 25. Mr. Cowper exhibited models of, and described the 

 most recent improvements in, paper-making -, and especially his own 

 machine for cutting paper made in sheets of unlimited extent into 

 such as were of proper size for ordinary uses. Some extraordinary 

 advantages of the powers of mechanism in paper-making and print- 

 ing were developed and illustrated in the course of the evening. 



In the Library was placed a beautiful series of anatomical models 

 in wax by M. Schloss. 



March 4-. Dr. Edmund Clarke gave an account of the present 

 state of Vesuvius and of Pompeii. This gentleman has ascended 

 that volcano several times, and attended particularly to its natural 

 history: the results of his observations were communicated in this 

 evening's discourse, and illustrated by many specimens of minerals, 

 plants, &c., and by numerous drawings. 



March 11. The beautiful machinery employed by Mr. Mordan 

 in the manufacture of pencils of the ordinary construction, the 

 points for the ever-pointed pencil, and the Bramah pens, was ar- 

 ranged in the Lecture-room in perfect working-order, and the ope- 

 rations were all explained by Mr. Ainger, whilst they were per- 

 formed by Mr. Giordan's men. 



In the Library, amongst many other objects of interest, was a 

 peculiar mountain barometer invented by Robinson, which could 

 be divided in halves and packed in a case not more than sixteen 

 inches long. There was also a portable transit instrument by the 

 same maker. 



March 18. The subject this evening was the Elasticity of matter 

 in general; particularly the elasticity of torsion in threads of glass; 

 with the application of this property to delicate physical research. 

 Mr. Ritchie, who treated this subject, resumed and illustrated what 

 he has already published upon it in the Philosophical Transactions, 

 adding several very beautiful experimental demonstrations of cer- 

 tain physical laws which have been established by mathematical 

 calculation. 



March 25. Mr. Faraday spoke on Light and Phosphorescence; his 

 object being to introduce to the members of the Royal Institution 

 certain experiments recently made in the laboratory by Mr. Pear- 

 sail, the Chemical Assistant, in which, after bodies phosphorescent 

 by heat, such as apatite, chlorophane, &c. &c. had been deprived, 

 by strong calcination, of their power of emitting light, it was proved 

 that it could be restored to them again. This was effected by 

 passing ten or twelve strong electrical discharges over them, and 

 it was observed, that at the same time there was a tendency to the 

 restoration of the colour of the fluor spar. 



Specimens 



