Minerals from Terlingua, Texas. 261 



described. In general due recognition is given of observa- 

 tions made by others, though it may not have been possible in 

 every case. 



Kleinite. 



Before describing the unique compound referred to in the 

 foregoing it will be necessary to impose on the reader a little 

 history. On the day preceding the appearance in Science of 

 the announcement regarding the new mercury-ammonium 

 compound there was read at a meeting of the Royal Prussian 

 Academy of Sciences a paper by Professor A. Sachs, of Bres- 

 lau, descriptive of an oxychloride of mercury which was 

 regarded by him as perhaps identical with the No. 5 of Pro- 

 fessor Moses, and to which he assigned the formula Hg 4 Cl 2 3 , 

 or 3HgO.HgCl 2 , and the name kleinite, after the eminent 

 mineralogist Prof. Carl Klein. This paper appeared in print 

 on Jan. 11, 1906. After reading the announcement of the 

 mercury-ammonium mineral, said to be also identical with the. 

 above No. 5 of Professor Moses, Professor Sachs made new 

 analyses of material in his possession and obtained results* 

 agreeing qualitatively in each case and quantitatively in one 

 with those which had already been obtained in Washington. 

 His later data appear in the table below : 



Sulphur-yellow crystals Orange crystals 



Hg ... ... 85-29 



CI ... ... 6-97 



S0 3 1-05 0-85 2-57 



NH 3 * 0-44 1-09 2-79 



He regarded the sulphur-yellow crystals as the purer, and 

 from the varying values for sulphur and nitrogen argued that 

 these could not be iutegral components of the mineral. With- 

 out committing himself to any view as to the molecular 

 arrangement, the following formula was suggested as the most 

 plausible— Hg 4 (Cl.£S0 4 ) a [O, (NH,),],- which is of the same 

 type as his original oxychloride, Hg 4 Cl 2 3 , but is far from 

 being in close agreement with his analytical data and is also 

 opposed to the chemical behavior of the mineral as a mercury- 

 ammonium compound. The assumption by Professor Sachs 

 of hydrogen and of oxygen other than that in the S0 4 radical, 

 was purely arbitrary, and it may be said here that his surmises 

 as to the formula of the mineral have not been verified by the 

 results of our work, nor have we found any certain difference 

 in composition between the light yellow and the orange crystals. 

 ♦Centralbl. Min. Geol. Pal., 1906, 200-202. 



