Geological Society. 465 



pound alloys, and 0*733 be accepted provisionally as the approxi- 

 mate density of hydrogenium. 



I have the pleasure to repeat my acknowledgments to Mr. W. C. 

 Roberts for his valuable assistance in this inquiry. 



Could the density of hydrogenium be more exactly determined, it 

 would be interesting to compare its atomic volume with the atomic 

 volumes of other metals. With the imperfect information we pos- 

 sess, one or two points may be still worthy of notice. It will be 

 observed that palladium is 16' 78 times as dense as hydrogenium 

 taken as 0*733, and 17*3 times as dense as hydrogenium taken as 

 0*711. Hence, as the equivalent of palladium is 106*5, the atomic 

 volume of palladium is 6*342 times as great as the atomic volume of 

 hydrogenium having the first density mentioned, and 6*156 as great 

 with the second density. To give an atomic volume to palladium 

 exactly six times that of hydrogenium, the latter element would 

 require to have the density 0*693. 



Taking the density of hydrogenium at 0*7, and its atomic volume 

 equal to 1, then the following results may be deduced by calculation. 

 The atomic volume of lithium is found to be 0*826 ; or it is less even 

 than that of hydrogenium (1). The atomic volume of iron is 5*026, 

 of magnesium 4*827, of copper 4*976, of manganese 4*81, and of 

 nickel 4*67. Of these five metals, the atomic volume is nearly 5 times 

 that of hydrogenium. Palladium has already appeared to be nearly 

 6 times. The atomic volume of aluminium on the same scale is 7*39, 

 of sodium 16*56, and of potassium 31*63. 



GEOLOGICAL SOCIETY. 



[Continued from p. 403.] 



April 14th, 1869.— Prof. Huxley, LL.D., F.BJ3., President, 

 in the Chair. 



The following communications were read : — 



3. " On the Salt-mines of St. Domingo." By P. Euschhaupe. 

 Communicated by Sir R. I. Murchison, Bart., F.P.G.S. 



The author described the Cerro de Sal, or Salt Mountain of St. 

 Domingo. It extends about 3 leagues in length, and consists, ac- 

 cording to the author, of rocks " of the Red Sandstone class " — which, 

 where the chief visible deposits of salt occur, are principally gypsum 

 schists, sometimes very argillaceous. The salt is generally surrounded 

 by an ash-like mass consisting of gypsum and clay. The author 

 compared the gypsum beds with those of the Keuper. The beds are 

 thrown into a perpendicular position, and the same change is ob- 

 servable for miles in the Savannas. An immense body of salt, 250- 

 300 feet broad, is exposed upon the north side of the mountain. 

 The salt is very white and pure, and might easily be conveyed to the 

 port of Barahona, about 18 miles distant. 



4. " A description of the ' Broads ' of East Norfolk, showing their 

 origin, position, and formation in the Valleys of the Rivers Bure, 

 Tare, and "Waveney." By B. B. Grantham, Esq., C.E., F.G.S. 



