274 Dr. J. E. Reynolds on certain Mineral Silicates. 



The other metals dropped oat of a glass funnel which termi- 

 nated below in a vertical tube of the diameter 2r in the clear. 

 The magnitude of the drop is then also determined by equa- 

 tion (3) ; yet it is far more difficult to obtain concordant results 

 than by the above method, even if the velocity of efflux of the 

 fused metal (which determines the size of the drop) is made as 

 small as possible. 



The capillarity-constants of fused metals a thus determined 

 are collated in the following Table, and, as a comparison, the 

 values found for mercury* and water f are added. The values 

 of « are given in milligrammes. The constant a } by which 

 Poisson designated the height to which a liquid rises against a 

 vertical side that it moistens, may be calculated by the aid of the 

 equation 





a* 





in which a is the specific gravity of the 

 compared with water. 



Capillarity- 

 constant. 



metal in question as 



Fu sing- 

 point. 



Platinum 



mgr. 

 . . 169-04 



> 1600 



Gold ... 



. . 100-22 



1200 



Tin . . . 



. . 59-85 



230 



Lead . . . 

 Mercury . 



. . (56-14) 

 . . 55-21 



330 

 -40 



Silver . . 



. . 40-94 



1000 



Glass 

 Water . . 



. . 1809 



. . 8 



(1100?) 

 



XXXVI. On certain Silicic Acids and the Anhydrous Mineral 

 Silicates. By J. Emerson Reynolds, Member of the Royal 

 College of Physicians, Keeper of the Minerals and Analyst to 

 the Royal Dublin Society %. 



THE recent changes which have taken place in the modes of 

 viewing chemical reactions and the constitution and me- 

 tamorphoses of the products of our laboratories, have hitherto 

 exercised but little influence upon the study of mineralogy. 

 Efforts have been made, as will presently appear, to replace the 

 old equivalent formula? of minerals by the atomic notation now 



* Pogg. Ann. vol. cv. p. 33 (1858). 



t Fortschritte der Physik, vol. xxxi. (1867) p. 107. 



+ Communicated by the Author. 



