1883.] 



On the Atomic Weight of Titanium. 



43 



The existing clouds will be furrowed obliquely, and the vortical stratum 

 will be cut up into diamond-shaped spaces, determined by the inter- 

 section of the old and new vortex-axes. This would explain the patch- 

 work arrangement commonly observed in mackerel sky. May not the 

 lengths of the patches give a measure of the rate of veering of one 

 of the currents ?— Jan. 4, 1884.] 



The above account of the formation of ripple-marks shows it to be 

 due to a complex arrangement of vortices. The difficulty of observa- 

 tion is considerable, and perhaps some of the conclusions may require 

 modification. I hope that other experimenters may be induced to 

 examine the question. 



Lord Rayleigh has shown me a mathematical paper, as yet 

 unpublished, in which he has considered the formation of aerial 

 vortices over a vibrating plate. It seems possible that an application 

 might be made of similar modes of approximation to the question of 

 water oscillating over a corrugated bottom. Even a very rough 

 solution would probably throw much light on the exact changes which 

 the ripple-making vortices undergo, and any guidance from theory 

 would much facilitate observation. 



" On the Atomic Weight of Titanium." By T. E. Thorpe, 

 F.R.S. Received November 7, i883. 



(Preliminary communication.) 



The sto'ichiometrical quantities which we ordinarily term atomic 

 weights are not only the fundamental constants of chemical calcula- 

 tions ; their relations as mere numbers are of the highest significance 

 in connexion with our conceptions concerning the essential nature of 

 matter. 



The recent publications of Becker and Clarke in America, and of 

 Lothar Meyer and Seubert in Germany, have served to demon- 

 strate on how slight an experimental basis a large number — the 

 greater proportion, it must be confessed — of the accepted values of 

 these constants really depend. 



A notable instance of this fact is seen in the case of titanium. 

 The atomic weight of this element was determined by Rose in 1829, 

 and by Pierre in 1847 with the following results : — 



Rose 48 -13 and 49 '58, 



Pierre 50 25. 



The commonly accepted value of titanium is that founded upon the 

 experiments of Pierre ; the atomic weight adopted by Mendelejeff in 

 the series based upon his periodic law is 48, a number which finds 



