CHEMISTRY. 295 



tory. Thus Mr. M. Chow has completed accurate determinations of the 

 electrode-potentials of Cu + CuCl, Cr, and of Bi + BiOCr, H+ + Cr, 

 and Mr. E. Zeitfuchs of that of Cu + Cul, I". Mr. W. A. Felsing has 

 determined the equilibrium conditions at 476° to 616° of the reaction 

 Ag2S-|-H2 = 2Ag + H2S, and Mr. E. .S. Freed those of the reaction 

 AgaS + 2H+ I- = 2Agi + H2S at 25°. 



A systematic investigation of the atomic structure of crystalline 

 substances by means of X-rays has been started, with the aid of Dr. 

 C. L. Burdick, who had previously worked mth Professor W. H. 

 Bragg in London. With the aid of research funds appropriated for 

 the purpose by each institution the expensive equipment required for 

 this work has been installed both at the Massachusetts Institute of 

 Technology and at Throop College of Technology, where it is expected 

 to continue the researches through a series of years. 



A study of chalcopyrite (CuFeS2) has already been completed, 

 whereby the location of the atom-lattices in this complex sulphide, 

 crystallizing in the tetragonal system, has been clearly estabhshed, 

 in a way which furnishes a further illustration of the interesting possi- 

 bilities of this new method of science. This research will soon be 

 published. A study of millerite (NiS) has also been nearly completed; 

 and one on arsenopyrite (FeAsS) and another on the sulphates of 

 barium, calcium, and lead are in progress. 



Remsen, Ira, Johns Hopkins University, Baltimore, Maryland. A problem 

 in tautomerism. 

 Some years ago I was engaged in an investigation on the constitution 

 of the two tautomeric forms of the chloride of orthosulphobenzoic 



acid represented by the formulas C6H4<[' ofv^/O and C6H4<^5.q p. 



These compounds can easily be obtained in any desired quan- 

 tity in pure condition. Their properties are such as to adapt them 

 to study. Inasmuch, therefore, as the phenomena of tautomerism 

 are of great interest and our knowledge of the subject is very inade- 

 quate, and, further, as there is no other example of tautom- 

 erism that lends itself to investigation as well as this, I planned an 

 extensive study of it. But my chemical activity was then seriously 

 interfered with by the necessity of taking up another kind of work, 

 and only a beginning was made in the prosecution of the larger investi- 

 gation I had in mind. Interesting results were obtained and an 

 account of these has been published.^ The main conclusion drawn 

 from these earlier experiments was that the high-melting chloride has 



the symmetrical formula C6H4<^^^ p,, and the low-melting chloride 



/CCl \ 

 has the unsynunetrical formula C6H4<^ ^^ ^^O. 



^American Chemical Journal, vol. 18, 791; 30, 247. 



