The remainder of the paper is taken up with a discussion of 

 this equation, and also of the case when there are n rings 

 symetrically disposed about the middle of the rod. The 

 subsidence of motion due to internal friction in elastic 

 solids has not been taken into account. 



General Meeting, October 16th, 1883. 



H. E. RoscoE, Ph.D., LL.R, F.R.S., &c., President, in the 



Chair. 



Mr. Harrj^ Baker, F.C.S., of Owens College, was elected an 

 Ordinary Member of the Society. 



Ordinary Meeting, October 16th, 1883. 



H. E. EoscoE, Ph.D., LL.D., F.E.S., &c., President, in the 



Chair. 



"On the leaves oiCatha edulis," byC. Schoelemmer, F.R.S. 



In a paper which I read before the Society a few months 

 ago* I stated that the custom of drinking coffee was intro- 

 duced into Arabia only in the beginning of the fifteenth 

 century. Before this time the beverage made of leaves of 

 kat (Catha edulis) was used and is still in use, possessing 

 properties resembling those of strong green tea, only more 

 pleasing and agreeable. From this it appeared to me highly 

 probable that kat contained caffeine, which occurs in tea, 

 coffee, and some other plants, all of which are used as 

 stimulants. 



Professor T. Thistleton Dyer, F.R.S., kindly supplied me 

 with fresh leaves of Catha, grown in Kew Gardens. Not a 

 trace of caffeine was found, while, to show its presence in 

 tea, a very few leaves are sufficient. 



* Proceedings, April 3rd, 1883. 



