190 



Blue oxide acts 

 as an acid more 

 powerfully 

 than the acid 

 itself. 



Elueish green 

 O2£idealsoacid. 



Molybdena 

 converted into 

 blue oxide by 

 water ut the 

 common tem- 

 peratureo 



Brown oxide 

 the same. 



ON INDIGESTION. 



teresting is, tliat they frequently occur in various operations 

 on molybdena, I shall confine myself here to a few of the 

 principal properties of the blue oxide. 1. It comports 

 itself altogether as an acid. It reddens blue paper more 

 quickly and more powerfully than the white acid ; and it 

 produces a brisk effervescence on combining with alkaline 

 carbonates, with which it furnishes a blue solution. We see 

 here a base combined with, a certain quantity of oxigen 

 manifesting a stronger acidity, than when it contains a 

 greater quantity of the acidifying principle; a very re- 

 markable anomaly. 2. This acidity still remains when the 

 blue oxide has passed to the state of blueish green oxide 

 (which reverts to its former state on the addition of an alka- 

 line corbonate). Its preparation shows its solubility in water, 

 but I have not yet ascertained the quantity water will take up. 

 JExp. 28. The manner in which metallic molybdena com- 

 ports itself, when heated in the open air, has already been 

 seen. Some phenomena, that occurred when I was ascer- 

 taining its specific gravity, led me to examine what would 

 take place on leaving it in contact with water at the ordinary 

 temperature. For this purpose I took thirty grains of 

 powdered molybdena, put it into a porcelain capsule, and 

 wetted it with water, which I left to evaporate slowly. 

 Having poured fresh water upon it, this afterward acquired 

 a blue colour: and this process being several times repeated, 

 the whole of the metal was converted into blue oxide. The 

 different degrees of intermediate oxidation observed in my 

 other experiments did not occur here. The brown oxide, 

 treated in the same manner, produced a similar result. 



fTo he concluded in our next. J 



VI. 



Remarks on the Formation of Acetous Acid in Cases of In- 

 digestion; by Mr. Perperes, Apothccarif, at Azilles. 

 Comrtiunicated by Mr. Pa RM en TIER*. 



Acetic acid ^^IIEMISTS at present are agreed in opinion, that 



foruiedimhe acetic acid is formed dvuing the digestion of certain sub- 



**"°'"^'''' • Annales de Chimie, vol. LX, p. 280. 



$tanc€s ; 



