1815.] in the Physical Sciences. 25 



Thus prepared, it has an acid, and f)eculiar taste and smell, quite 

 different ffom that of acetic acid. When cooled down sufficiently, 

 it becomes solid, but does not crystallize. Its specific gravity was 

 1'1168; and, when diluted with its own weight of water, the 

 specific gravity Ijecomes 1-060; and when with twice its weight of 

 water, it becomes I 0290. In all these respects acetic acid is very 

 diflerent. It likewise requires dift'erent proportions of bases to 

 neutralize it. Gehlcn describes minutely the formates of copper 

 and barytes, and compares them with the acetates of the same 

 bases. They differ in colour, solubility, form of crystals, and all 

 their other properties, from each other. 



2. Ferrurett'd Chyazic Acid. — Mr. Porrett has discovered two 

 new acids, and rendered it probable that many more exist. Ferru- 

 reted chyazic acid is obtained from the salt formerly called triple 

 prussiale of hai-ytes. Tiiis salt is dissolved in water, and as much 

 sulphuric acid added as is just suflicicnt to neutralize the harytes 

 present. The mixture, being agitated in a phial, is set aside for 

 some time. Sulphate of barytes precipitates, and the ferrureted 

 chyazic acid remains in solution in the liquid. Its properties are as 

 follows : — 



It has a pale lemon colour; but no smell. It is decomposed by 

 a gentle heat, or by exposure to a strong light. Prussic acid is then 

 formed, and white triple prussiate of iron, which is soon changed 

 into Prussian blue. It separates acetic acid from all its combina- 

 tions. It combines with tlie different bases, and forms the salts 

 formerly called triple prussiates. This acid is composed of four 

 constituents ; namely, black oxide of iron, carbon, hydrogen, and 

 azote ; or perhaps it would be as well to consider it as composed of 

 five constituents, oxygen, iron, carlon^ hydrogen, and azole. It 

 would be a curious, but very difficult problem, to determine the 

 proportions in which these ditierent constituents are united in this 

 complicated acid. How many atoms of each enters into it. From 

 the great permanency of this acid when compared with some of the 

 vegetable and animal acids, one would be disposed to suspect that 

 its composition is very simple. Perhaps an atom of each constituent 

 would not be very far from the truth. 



According to JVlr. Porrett, fenureted chyazate of potash is com- 

 posed of 



Black oxide of iron . .17"2G 7 r- i i • •, 



Prussic acid 30' 10 \ F^""f<^»ed chyazic acid . . ^'J-GG 



Potas-h 39'3t 



Water 13.00 



100-00 



This analysis cannot be reconciled with the supposition of ferru- 

 reted chynzic acid beit-g a cornpoimd of an atom of each of its 

 constituents. If we suppose the salt composed of an atom of acid 

 and an atom of base, as is usual with the salts of potash, then an 



(i 



