192 Scientific Intelligence. — Mineralogy. 



ted through a bed of clay, which covers the natural carbonate 

 of soda, called urao, at Lagunilla, a small Indian village to the 

 south-east of the town of Merida in Spanish America. 



20. Titanium, ageneral ingredient in Felspars and Serpentines. 

 -Peschier, in Ann. de Chem. and de Phys. March 1826, finds, by 

 experiments, 1.9/, That Titanium is a constant constituent part of 

 felspars and serpentines ; ^d, That serpentines, like felspars, con- 

 tain an alkaline principle. And he adds, that his researches de- 

 monstrate that the greater number of primitive mountain rocks 

 contain titanium, and that the metal is more generally distributed 

 in nature than is commonly supposed. The glassy felspar Pe- 

 schier finds to contain both potash and soda. 

 21. Fluids in Cavities of Minerals. — Many beautiful specimens 

 ' of amber, containing cavities more or less filled with water and 

 air, are drawn and described in Sendeiio's Historia Succinorum. 

 Sokolow, we are informed, on breaking a rock crystal in 

 which a fluid was inclosed, heard an explosive noise, and re- 

 marked that the hand- tow el in which the specimen was held 

 when breaking it, appeared in several places as if acted on by an 

 acid. (Communicated to Lconhard by Von Struve). 



GEOLOGY. 



22. Contested passage in Tacitics. — In Tacitus Ann. Lib. xiii. 

 c. 57., it is said, " Sed civitas Juhonum socia nobis, malo impro- 

 viso afflicta est ; nam ignes, terra editi, villas, arva passim corripier 

 bant," &c. This passage some consider as an historical proof of 

 volcanic eruptions on the Rhine and in the Eifel, — an opinion not 

 in dhe least probable. We are disposed, with Nees von Esen- 

 beck and others, to refer the whole to some muir or heath burn- 

 ing that had taken place near Cologne. 



23. Hills formed by Springs. — The wells of Moses, near to 

 Suez, afford, according to Monge, the remarkable appearance of 

 hills formed by springs. The eight wells of this watering place 

 all occur on the summits of small conical hillocks, having crater- 

 shaped hollows at top, forming basins, in which the water collects, 

 and from which it flows downwards in natural ravines. The 

 highest of these hillocks rises 40 feet above the surrounding 

 country. In it the spring has long ceased to flow. The other 



