IOWA ACADEMY OF SCIENCES. 85 



Mercurous nitrate gives a black precipitate. 

 Nickel sulphate gives a whitish-green precipitate. 

 Manganese chloride gives a white precipitate. 

 Ferric chloride gives a yellow precipitate. 

 Ferrous sulphate gives an olive green precipitate. 

 Zinc chloride gives a white precipitate. 

 Baryta gives a white precipitate. 



SODIUM CARBONATE. 



Copper sulphate gives a tnrquois blue precipitate. 



Lead acetate gives a white precipitate. 



Mercuric chloride gives a light yellow precipitate which 

 turns brownish red. 



Nickel sulphate gives a whitish green precipitate. 



Manganese chloride gives a white precipitate. 



Ferric chloride gives a brown precipitate. 



Ferrous sulphate gives an olive green precipitate. 



Zinc chloride gives a white precipitate, 



Barium chloride gives a white precipitate. 



It will be observed that the only essential difference in 

 the precipitates yielded by "Menke's hyponitrite" and 

 sodium carbonate is in case of ferric chloride which yields 

 a brown precipitate instead of a yellow one, and that might 

 even be described as yellow in dilute solution. 



We presume that Menke did his work under the eye of 

 Professor Bloxam, and he did not seem to doubt it in any 

 way. In his text-book on Inorganic and Organic Chemistiy, 

 page 145, he states that "the sodium salt may be prepared 

 in large quantity by fusing sodium nitrate with iron filings 

 in an iron crucible." 



It may be said that other methods have failed in the 

 hands of those who followed the discoverer. Zorn prepared 

 alkaline hyponitrite by reducing nitrates with ferrous 

 hydroxide, but for some years afterwards, those who followed 

 him failed in their attempts to apply his method. Not- 

 withstanding all that can be said in favor of Menke's 

 method, while it is still possible, it would seem evident 

 that he mistook sodium carbonate for sodium hyponitrite. 



