144 Scientific Intelligence. [August, 



quartz, in a massive form ; there in mica, in large plates, and 

 very frequently rich in iron and cinnauion-stone. Garnet, 

 traces of the ruby, and adularia, were the only minerals which I 

 observed ; but I have no doubt more minute examination would 

 have detected others, and particularly the corundum, all the 

 varieties of which, including the finest blue sapphires, are found 

 in considerable abundance in the alluvial country at the foot of 

 the mountains." 



Dr. Davy remarks that the height of Adam's Peak has been 

 much exaggerated, and that the estimate of 15-000 feet is evidently 

 incorrect. From his barometrical observations, he is disposed 

 to think that it does not exceed 6343 feet above the level of the 

 sea ; but as the author himself acknowledges, this conclusion 

 cannot be regarded as more than an approximation to the truth, - 

 as there was.no barometer at the bottom of the mountain to 

 compare with the one at the top. This deficiency is, however, 

 less important in the tropical regions, where the weight and 

 temperature of the atmosphere are so nearly stationary. 



V. On the Acidity of Tungsten and Uranium when saturated 

 with Oxygen. By M. Chevreul.* 



When the tungstate of ammonia is calcined, a yellow powder: 

 remains, which is tungsten saturated with oxygen. Many 

 chemists having observed that this powder had no action upon 

 litmus, have concluded that tungsten saturated with oxygen was 

 not properly entitled to the appellation of an acid. M. Chevreul 

 wishing to assure himself of the fact, whether tungsten satu-' 

 rated with oxygen, which had no sensible affinity for acids, but' 

 which, on the contrary, had a very decided one for alkalies, did 

 not redden litmus, heated tunstate of ammonia with litmus, 

 when he observed that the ammonia was disengaged, and that 

 the litmus was reddened ; hence he concludes that what has 

 been called tungstic acid possesses a real acidity. M. Chevreul, 

 when he communicated this observation to the rhilomathic 

 Society, stated that since he had performed the experiment, 

 he found a similar remark in the memoir of the D'Elhuyarts. 



The peroxide of uranium is known to have the property of 

 being dissolved in the sub-carbonate of potash, but it is not 

 generally known that the native peroxide of uranium, and that 

 which is formed from the nitrate, after having been decomposed 

 by heat, causes litmus to assume the red colour ; likewise that 

 the peroxide of uranium heated with a solution of the sub-, 

 carbonate of potash, is dissolved in it without disengaging any 

 carbonic acid; and that the solution, which has a beautiful 

 lemon yellow colour, when sufficiently concentrated, affords 

 crvstals of the same colour. 



M. Chevreul has observed that the peroxide of urani lm cause* 



* Bulletin des Sciences for 1818, p. 20. 



