282 Mr. M. M. Pattison Muir on Gallium. 



prises certain of those elements which form oxides having the 

 general formula E 2 3 , viz. boron, having the atomic weight 

 of 11, aluminium == 27, yttrium = 88, indium = 113, didy- 

 mium = 138(?), erbium = 178(?), and thallium =204. But 

 when this group is compared with others with which it ought 

 (theoretically) to present certain analogies, it becomes evident 

 that there are several gaps in the series. These gaps M. Men- 

 delejeff has filled with hypothetical elements. Two vacant 

 places occur between aluminium and indium : to the second of 

 these the hypothetical metal ekaaluminium is assigned. The 

 analogies between this metal and aluminium, on the one hand, 

 and indium, on the other, should be, according to theory, 

 somewhat the same as those existing between zinc and magne- 

 sium and cadmium, or arsenic and phosphorus and antimony. 



In the paper already referred to, the theoretical properties of 

 ekaaluminium and of some of its salts are detailed. M. Men- 

 delejeff then puts forward the suggestion that the new metal 

 gallium, discovered August 3, 1875, by M. de Boisbaudran, is 

 very probably no other than the hypothetical ekaaluminium. . 



Since the publication of MendelejefFs paper, various notes on 

 gallium and on its salts have been published by the discoverer. 

 In many respects the observed properties of this metal corre- 

 spond with the properties which MendelejefFs theory assigns to 

 ekaaluminium. I have tabulated the leading properties of 

 gallium and of its salts, and have placed alongside of these 

 descriptions others, of the properties of the analogous salts of 

 aluminium and indium. I have also tabulated a few of the 

 hypothetical properties of ekaaluminium as detailed by Men- 

 delejeff in the paper already referred to. 



M. de Boisbaudran does not apparently altogether accept 

 the position assigned to ekaaluminium for his new metal gal- 

 lium. Further researches must of course be forthcoming 

 before a decided opinion can be given. Would it not be well 

 that these researches should in the first place take the direc- 

 tion indicated by the hypothetical properties of ekaalumi- 

 nium ? MendelejefFs hypothesis is at least of much value as 

 a guide to future research. 



I am, Gentlemen, 



Yours truly, 



M. M. Pattison Muir. 



The Owens College, Manchester. 

 February 24, 1877. 



