108 SCIENCE PROGRESS 



that metallic copper was somewhat soluble but Seely (5) showed 

 that this was not the case if air and moisture were excluded. 



More recently much work on solubilities in ammonia has 

 been carried out by Franklin and Kraus in America (3). They 

 confirmed most of Gore's work and have found that very many 

 organic compounds are soluble in liquid ammonia. Most of the 

 aliphatic halogen compounds, monohydroxy alcohols and ethers 

 are miscible with ammonia ; so also are the aldehydes and 

 acids, except those of high molecular weight, such as palmitic 

 and stearic acids. The sugars are easily soluble but dulcitol 

 and mannitol are almost insoluble. The hydroxy-acids, amino- 

 acids, amides and ureides are mostly readily soluble ; amines 

 and esters vary much amongst themselves, though most are 

 soluble to some extent, whilst most of the dibasic acids are 

 insoluble. The foregoing remarks apply to aliphatic substances 

 only. The solubility of the aromatic compounds in many 

 groups varies so much with the individual compounds that it 

 is difficult to give a general statement. Phenols, alcohols, ethers, 

 monobasic acids and esters in general are readily soluble ; de- 

 tailed information on this subject can be found in the publications 

 ■of Franklin and Kraus. 



Ammonium and its Metallic Derivatives 



In order to amplify the ammonium radicle theory of Ampere 

 and Berzelius, a series of investigations was begun by Weyl (4) 

 in 1864. His work included many observations on complex 

 ammonia compounds of mercury and other metals which are 

 not of great general interest. By the action of dry ammonia 

 under pressure on metallic potassium or sodium, Weyl obtained 

 a copper-red metallic-looking liquid, which he thought was 

 probably ammonium in which one of the hydrogen atoms had 

 been substituted by an atom of the alkali metal, NH 3 Na. 



Weyl's work was severely criticised by Seely (5), who denied 

 that a compound was formed when sodium dissolved in liquid 

 ammonia. He regarded the blue liquid so formed as an ordinary 

 solution, the solid becoming liquefied in precisely the same 

 way as sugar becomes liquefied when dissolved in water. When 

 the liquid is evaporated the solid is left in its original form with 

 its properties unaltered. Recent work with this blue solution — 

 to which reference will be made later — seems to confirm Seely's 

 views ; but some further work of his gave indications of the 



