374 SCIENCE PROGRESS 



but' oxidation takes place, and the yield of the new compound 

 and its properties suggest that it is not a simple derivative of 

 either diacetylacetone or dimethylpyrone. 



The compound C^H^Ogl is a strong acid, liberating carbon 

 dioxide from carbonates, and forming metallic salts ; the iodine 

 is readily removed by warm dilute silver nitrate and nitric 

 acid, but boiling with concentrated sodium hydroxide solution 

 does not bring about decomposition. Chlorine water does not 

 liberate iodine, but treatment in the cold with a solution of 

 bleaching powder gives a precipitate of calcium carbonate ; 

 this reaction is quantitative, three carbon atoms being con- 

 verted to carbonate. It is a monobasic acid of molecular 

 weight, approximately 263, forms a mono-acetyl derivative, 

 and reacts with two molecules of phenylhydrazine ; it is stable 

 to boiling water, but heated with water to 130-140° it decom- 

 poses quantitatively into hydriodic acid, acetic acid, carbon, 

 and water 



C^H^I -> HH- CH3 • CO2H + SC + H2O, 



certainly a remarkable reaction. 



The authors consider that the only simple formula which 

 agrees with these properties is : 



CHa-CO-CH CH 



HO • C CO 



CH. 



On salt formation the elements of water are added, the iodine 

 becoming quinquivalent. 



The authors draw attention to the fact that a compound 

 containing iodine in a ring with four carbon atoms has been 

 described previously, and found to be a base ; in the above 

 example the compound contains an iodine atom in a ring 

 with five carbon atoms, and is an acid. This is the converse 

 of the behaviour of nitrogen in pyrrole and pyridine. 



MINERALOGY AND CE-YSTALLOGRAPHT. By A. Scott. D.Sc. 



The development of crystals with curved faces is fairly common, 

 and numerous explanations of the phenomenon have been 

 advanced. In an interesting paper on the ternary alloys of 

 tin, antimony and arsenic, J. E. 3t«ad (Journ. Inst. Metals, 22, 

 127, 1 91 9) describes some compounds which show this develop- 

 ment of curvature in a remarkable degree. From melts con- 



