French Katioval InJl'Unle, 37 1 



each time the gas to be ufed, bv wafliing it with a folution 

 of copperas, or fulphat of iron; which, according to his 

 t)pinion, will abforb all the nitrous gas, but leave the azot, 

 which is mixed with it. 



It is this aftion of the fulphat of iron, or nitrous gas, 

 with which Berthollet has l)een occupied ; and it was on it 

 indeed that the folution of the problem depended. He has 

 found that under this circumftance, as well as under a muU 

 titudr of others, the nitrous gas is not only abforbed, but 

 decompofed, and that it abandons a part of its azot to con- 

 vert itfelf into nitrous acid. He is of opinion that the nitrous 

 gas may differ in the proportions of its two principle*, 

 oxygen and azot: but that it dues not contain azot in fimple 

 mixture. 



Thefe intereftindf refults are the confequcnces of the au- 

 thor's ideas on chemical affinities, communicated to the 

 public above fix months ago. He has made a new appli- 

 cation of them by comparing the action of the metallic 

 oxyds on fubftances, fuch as acids, the compofition of 

 which is invariable ; and he has proved that the a6lion of 

 thefe oxyds is modified by their ftate of oxydation ; that 

 the more they are oxydated, for example, the lefs affinity 

 thev have for the nitric and fulphuric acids, while a contrary 

 etTcft takes place with regard to the muratic acid. Befides, 

 the combinations of thefe oxyds with other fubftances depend 

 alfo, whatever may be the ftate of their oxydation, on the 

 proportion in which they enter into thefe combinations. 

 All the phenomena therefore depend on the proportions, 

 and- not on the conftant affinity peculiar to each metal. 



Three memoirs have been prefented on natural hiftory 5 

 one of thefe, by Lacepedc, contains feme obfervations on 

 the ant-eater, an American animal, which lives only on 

 ants. The author has reftified the dcfcription given by 

 Buffon of the fecond fpecies of this animal, called tamandiia^ 

 and defcribed a blackifh variety hitherto undefcribed. 



The fecond memoir is on the ibis of the antients, by 

 Cuvi«r. The author has difcovercd from mummies, mo- 

 numents, and the dcfcriptions of Homtr and Plutarch, that 

 this bird was not the famaas that which modern naturalilts 



3 B 3 have 



