RECENT ADVANCES IN SCIENCE 563 



dimension vertical as is required by the theory. The molecule 

 of tristearin has the same length perpendicular to the surface 

 as the stearic acid molecule, but three times the cross section. 

 Thus each of the three active groups is drawn down to the 

 surface of the water while the hydrocarbon chains are packed 

 in side by side, and are erect upon the surface. 



ORGANIC CHEMISTRY. By P. Haas, D.Sc, Ph.D., St. Mary'i 

 Hospital Medical School, London. 



The anomalous behaviour of the first member of a homo- 

 logous series is particularly well illustrated by the case of 

 formaldehyde, which in many of its reactions differs entirely 

 from its homologues, and a few recent examples of the study 

 of such reactions deserve notice. Thus Werner (/. Chem. Soc. 

 191 7, 111, 844) has recently been re-investigating the question 

 of methylation by means of formaldehyde with special reference 

 to the mechanism of the interaction of formaldehyde and 

 ammonium chloride. This reaction leading to the formation 

 of methylamine and dimethylamine was previously studied by 

 Brochet and Cambier (Bull. Soc. Chem. 1895, [ IIJ ]> 13> 392) 

 and others who assumed that complex condensation com- 

 pounds were formed in the first instance, and that these subse- 

 quently decomposed into the simple amines. Werner, how- 

 ever, finds that when commercial formalin, containing methyl 

 alcohol, is heated with ammonium chloride a volatile liquid is 

 produced containing methyl formate and methylal, while 

 carbon dioxide is evolved at the same time. The methylal 

 of course is formed by the interaction between the aldehyde 

 and its alcoholic impurity, but the production of methyl for- 

 mate and carbon dioxide point to the oxidation of some of 

 the aldehyde. The following equations are put forward as 

 a probable explanation of the reactions ; the first product 

 methylene amine (I) 



HCHO + NH 3 . HC1 = CH 3 : NH . HC1 + H 2 



(i) 



being an unsaturated compound is readily oxidised at the 

 expense of the water present, which simultaneously reduces 

 another molecule of formaldehyde as follows : 



CH 2 : NH . HC1 + H 2 i O + HCHO = CH.NH, . HC1 + HCOOH 



