= 21 1 



(-)=2lJ 



RECENT ADVANCES IN SCIENCE 369 



reaction is capable of giving rise to ions of both kinds. The 

 nature of these ions has not yet been determined. 



Whilst the investigation of Pinkus represents an important 

 preliminary step, it is obvious that much remains to be done. 

 Thus it would be very desirable to know if a simple gaseous 

 dissociation such as that of molecular iodine into its atoms is 

 accompanied by ionisation. That is, whether the reaction goes 

 according to the scheme : 



I 8 =2l 



or according to the schemes : 



I 3 =I + +I- = 

 or I 2 = 2l + -f 2(- 



So far as the writer is aware nothing is known about such a 

 point. Undoubtedly the necessary temperature would render 

 the experimental test difficult. In the same connection the 

 question arises as to the relation of the so-called " resonance " 

 potential and the ionisation potential of a gas to the chemical 

 change involved. Even yet we do not appear to be in a position 

 to state exactly what occurs when a gas is ionised. 



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

 Hospital Medical School, London. 



A new method of preparing aldehydes is described by Rosen- 

 mund (Berichte, 191 8, 51, 585) ; it consists in reducing an acid 

 chloride dissolved in dry xylene by means of hydrogen bubbled 

 through the boiling solution in the presence of palladinised 

 barium sulphate containing 5 per cent, of metal ; hydrogen 

 chloride escapes through a reflux condenser and the aldehyde 

 may finally be isolated by distillation from the sodium bisul- 

 phite compound. The method gives very good yields, and 

 appears to be one of the most convenient methods yet de- 

 vised for the preparation of aldehydes. Treated in this way 

 benzoyl chloride gave a 97 per cent, yield of benzaldehyde, 

 while butyric aldehyde was obtained in 50 per cent, yield from 

 butyryl chloride. 



An interesting example of the influence of conditions upon 

 the catalytic activity of platinum has been recently published 

 by Willstatter and Jaquet (Berichte, 191 8, 51, 76y). It has 

 been shown by Hesse (Berichte, 191 3, 46, 3120) that for the 



