RECENT ADVANCES IN SCIENCE 127 



the British journals, that of Chattaway on the preparation of 

 perhaloid derivatives of ammonium may be selected as of general 

 interest {Trans. Chem. Soc. 191 5, 107, 105). Under suitable 

 conditions the addition of a chlorine and an iodine atom to 

 ammonium chloride can be brought about, giving scarlet prisms 

 possessing the formula NH 4 C1 2 I. Other compounds, such as 

 NH 4 C1J (golden-yellow prisms) and NH 4 ClBrI (garnet-red 

 prisms), were prepared in the solid state. These compounds 

 appear to be fairly stable ; they can be heated to 200 C. 

 without decomposition, and 'are not attacked by water, in which 

 they are readily soluble. It is noteworthy that the introduction 

 of the extra halogen atoms at the same time brings about the 

 phenomenon of colour. 



Quite a remarkable advance in our ideas on the chemical 

 reactivity of iodine is the result of the recent work of Kappeler 

 and Fichter on the formation of iodine salts. Considering the 

 halogen family of elements, it might have been expected that 

 if metallic properties were exhibited at all by this typically 

 acidic natural group, they would appear in iodine as the 

 heaviest member of the group. This has now been realised, 

 and in the latest paper dealing with the subject (Zcit. anorg. 

 Chem. 191 5, 91, 134) such compounds as iodine sulphate, I 2 (S0 4 ) 3 , 

 iodine perchlorate, I(C10 4 ) 3 . 2H2O, and iodine periodate, I(I0 4 ) 3 

 are described, in which the versatile iodine atom functions as 

 a trivalent metallic radical. 



The extensive work of Franklin and his collaborators on 

 reactions in liquid ammonia solutions have been further ex- 

 tended in several papers published in the Proceedings of the 

 National Academy, U.S.A. This field of work has been ex- 

 tremely fruitful in producing long series of inorganic compounds 

 in which the amino- and imino-groups function largely. The 

 work has now been extended to include several organic deriva- 

 tives, and may in future lead to important methods for the 

 production of amino-acids. 



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

 Hospital Medical School. 



The working out of processes for the synthetic production of 

 compounds from new or unfamiliar sources is always to be 

 regarded as a valuable contribution to science, but at the present 

 time, when the customary sources of supply of any substances 



