in 



Flint — Researches ujpon the Goriiplexitii of Telluriutn. 215 



material, to have the atomic weiglit 127"5, generally accepted 

 for telliirinm. Kepeated hydrolysis with hot water of a solution 

 of 500 grams of this preparation in hydrochloric acid has 

 furnished, in ten fractionations, a product consisting of twenty- 

 three grams of dioxide. The tellurium in this fraction, it has 

 been demonstrated, also by the basic nitrate method in seven 

 experiments using twenty-one grams, has an atomic weight of 

 124'3. Two intermediate fractions, estimated in the same way, 

 give values of 126'6 and 125"4 respectively, these three results 

 taken together exhibiting a progressive diminution of the 

 atomic weight. 



In March of the year 1S69, Mendeleeff, in announcing the 

 periodic law, made the following statement:* " Die Atomge- 

 wichtsgrdsse eines Eleinentes kann bisweilen corrigirt werden, 

 sobald seine Analogien bekannt sind. So muss dass Atomge- 

 wicht des Te nicht 128, sondern 123-126 sein." The problem 

 •inferentially stated by him, which for the last forty years has 

 supplied the subject matter of researches too numerous to 

 mention, appears to have been solved, and affirmatively, by the 

 research herein described. 



Brauner'sf various low results which he published in 1889 ; 

 Heberlein's:}; value of 126-99 ; Steiner's,§ of 126-4, obtained 

 in 1901 by fractional distillation of diphenyl telluride ; Marck- 

 wald's,!! of 126-85 in 1907, from fractional crystallization of 

 telluric acid ; and the figure 126-53, found in 1909 by Brown- 

 ing and Flint,^[ using hydrolysis with water, have been the 

 chief divergences in the past from the accepted value. 



The present investigation has furnished more than twenty 

 grams of a purified product possessing an atomic weight of 

 124-3. Since this preparation was extracted from a large quan- 

 tity of material which is proved by its atomic weiglit, 127*45, 

 to correspond to what has been hitherto considered elementary 

 substance, the figure 124-3 is apparently the nearest approach 

 which has yet been made to the true atomic weight of the 

 element tellurium. 



Part II. 



(Preliminary.) 



Experiments upon a Fractionation hy Nitrie Acid. 



In the purification of some crude tellurium by three crystal- 

 lizations from nitric acid, by the method of Norris, Fay, and 

 Edgerly,** it was observed that a part was rather more insol- 

 uble than the rest, in the nitric acid used (sp. gr. 1*25). A sep- 



* C. f. Ber., xiii, 1799. ^ Ber., xxxiv, 570. 



t J. Chem. Soc, Iv, 382. || Ber., xl, 4730. 



X Dissei-t. Basel, 1898. T[ Loe. cit. 



** Am. Chem. Jour., xxiii, 105. 



