108 REPORT— 1891. 



periods, however, a glance at the curve shows that the only- 

 elements undoubtedly on descending portions are beryllium 

 and magnesium. The evidence for the existence of alkyl 

 compounds in either case is so slight that one may be pardoned 

 for doubting whether the short periods are exceptional after 

 all. The only evidence of beryllium alkyl compounds comes 

 also from Cahours, and his observations were of a purely 

 qualitative character. About the alkyl compounds of boron 

 and aluminium there is, of course, no uncertainty whatever ; 

 but these elements occur at the minima of the curve, and they 

 naturally differ in their properties from the metals of the 

 eighth group, which are at the minima of the long periods. 



I believe that magnesium should be classed, as to the 

 power of forming free alkyl compounds, with calcium, strontium, 

 and barium, which do not, rather than with zinc, cadmium, 

 and mercury, which do. This agrees with the arrangement 

 of the elements of Group II., which is suggested by the 

 majority of the chemical, and by at least some of the physical, 

 properties of magnesium. It is still, however, possible, as 

 indicated by Wanklyn's solitary qualitative experiment, that 

 magnesium can form an unstable double ethide with zinc. If 

 so, it resembles sodium more closely than any other element 

 from this point of view ; which is likely enough, as sodium is 

 its immediate predecessor in the natural series in which it 

 occurs. 



3. Unsuccessful Attempts to prepare Magnesium Ethyl. 



By N. T. M. WiLSMORE, B.Sc. Melb. 



(Communicated by Orme Masson.) 



This research was undertaken at the instance of Professor 

 Masson, of this University, to whom, and also to Mr. J. B. 

 Kirkland, F.C.S., I am indebted for much valuable help and 

 advice throughout the course of the work. 



There are, so far as I am aware, only three notices of mag- 

 nesium ethyl previously published — namely, Hallwachs and 

 Schafarik, Annalen, 109, p. 206 (1859) ; Cahours, Ann. de 

 Chim. et Phys., Iviii., 3° series, p. 17 (1860) ; Wanklyn, 

 Journ. Chem. Soc, xix., p. 129 (1866). 



Hallwachs and Schafarik heated magnesium filings with 

 ethyl iodide in a sealed tube. The action began at the ordinary 

 temperature, and was completed by heating to 180°. About 

 6 grammes of ethyl iodide were used up in one day. The metal 

 was then converted into a white mass, no liquid remaining in 



