Ewart Johnstone's way to prepare 

 Nitric Oxide. 



By 

 IVIasumi Chikashige, Rigakushi, 



College of Science, Imperial University. 



In IHH'2 D. Ewnrt Johnstone nnnonnced in the Chemical News, 

 45, 159, that cobalt nitrate and potassiiun rliiocvanate heated together 

 readily yield nitric oxide. Exce])t by Schertel, in the Befcrate of the 

 Berichte of tlie (h'niKDt Chemical Socirtji, thi« announcement seems to 

 have been received AviHiont criticism, and Michadis inserted it in his 

 edition of Graliam-( )rt()'.s J)tnr(j(inic Chnnistrii amon,u- the methods of 

 preparing nitric oxide. 



The results of mv own testing of the method oblige me to con- 

 clude that Johnstone is altogether wrong. We are directed by him to 

 mix four parts of a solution of potassium thiocyanate with one part of 

 a solution of cobaU nitrate, such as are ordinarily in use in the 

 laboratory, and genrlv heat the mixture, when nitric oxide will be 

 copiously evolved. An equation is given of the action in which 

 four molecules of the potassium salt and one of the collait salt 

 appear, and since the quantities to be taken are so indefinitely 

 set down, I started my experiments wnth these proportions of the 

 salts, both practically in a state of purity. The result ])roved 

 that, in these proportions, as well as in many others which were 

 tried, whether the s<:)lutions are dilute (jr concentrated, only gently 

 heated or freely boiling, nitric oxide is not formed at all by 



