280 



Dr. W. C. Anderson and Mr. G. Lean. [June 16, 



Gautier. Carrick Anderson and Lean. 



Per cent, of AL 



100 

 90-01 

 71-93 

 56-63 

 43-50 

 24-80 

 20-20 

 17-43 

 15-57 

 13-31 

 10-65 

 8-33 



0-5 

 0-0 



Temp, of 

 separation. 



665 



649 



630 



622 



608-5 



563 



560 



561 



549 



544 



537 



515 



228228-5 

 232 



Action on Water. 



A remarkable feature of the alloys of the aluminium-tin series, to 

 which we directed attention in our previous paper, is the readiness 

 with which they decompose water with evolution of hydrogen even at 

 ordinary temperatures. The phenomenon is exhibited by every one of 

 the long series of alloys we have prepared, and in all cases the action 

 is greatly intensified by warming the water. In consequence of this 

 action, polished plates left in even slightly damp air become in a few 

 days strongly pitted, and when the phenomenon was mentioned by 

 one of us to the late Sir W. Roberts- Austen, he recalled that 

 certain alloys of these metals, which had been prepared at one time in 

 the Mint and laid aside, were found after a period to have crumbled to 

 powder. We have not noticed the effect so fully developed in any of 

 our specimens, but some which have been for two years in loosely- 

 corked tubes are now becoming swollen and distorted. 



In the paper already quoted we stated that we had not then been 

 able to obtain any concordant results for the evolution of hydrogen in 

 the case of the different alloys that mighi show a connection between 

 the hydrogen given off and the aluminium contained in the alloy. We 

 experimented at the time on alloys cast in chilled moulds, and the 

 same annealed for several hours at various temperatures in the region 

 just below redness. The figures showed, however, that the cast metal 

 always yielded more hydrogen than annealed specimens containing the 

 same proportion of aluminium. In repeating the experiments the 



