108 $. L. Penfield — Canfieldite, a new Germanium Mineral. 



thanks to him for the liberality with which he has placed an 

 abundant supply of this valuable material at his disposal. It 

 is in acknowledgment of these services that the mineral has 

 been named after him. 



It is unfortunate that at the present no further information 

 can be given concerning the exact locality and mode of occur- 

 rence, but from inquiries that have been set on foot by Mr. 

 Canfield it is hoped that full data concerning these points will 

 be given later. 



When the mineral was brought to the writer, attempts made 

 to identify it at once showed that it was not one of the ordi- 

 nary silver minerals. Thus in the open tube it gave a reaction 

 for sulphur but no sublimate. In the closed tube with a 

 Bunsen burner flame only a slight sublimate of sulphur, but at 

 a higher temperature with a blowpipe flame the sulphur in- 

 creased, while nearer the assay a pale yellow sublimate formed, 

 which became lighter on cooling. On examining this with a 

 lens it was found to consist of minute globules most of which 

 were nearly colorless but some were yellow. Boiling concen- 

 trated nitric acid was found to attack and oxidize the mineral 

 very slowly. On charcoal in the oxidizing flame it fused read- 

 ily and gave almost immediately a pure white sublimate near 

 the assay, but no color to the flame. On continued blowing 

 this sublimate moved farther out, assuming a color which 

 varied from greenish to brownish yellow, for the most part 

 lemon yellow, while the assay changed to a pure silver bead. 

 On examining the coating more minutely with a lens it was 

 seen to have a peculiar smooth appearance, as if it had fused 

 on the surface of the charcoal, while scattered about nearer 

 the assay were numerous small transparent to milk white 

 globules, along with minute globules of silver. These tests 

 led to the suspicion that the mineral might possibly contain 

 germanium and a comparative test, made with argyrodite on 

 charcoal, gave exactly the same results. It is to be noted here 

 that while Richter* describes very minutely the reactions which 

 argyrodite gives on charcoal he does not mention the smooth 

 surface of the coating or the formation of the fused globules 

 which form so characteristic and useful a test for the identifi- 

 cation of germanium. In order to prove beyond all doubt the 

 identity of the element thus indicated with germanium the 

 properties of the element as given by Winklerf were studied, 

 a series of careful qualitative tests were made together with 

 the formation of most of the important compounds mentioned 

 by him. Thus a sulpho-salt, soluble in alkaline solutions like 

 those of the tin, arsenic and antimony group, w T as prepared, 



* Quoted by Weisbaeh, Jahrb. f. Min., 188(5, ii, p. 67. 

 f Journ. i. prakt. Chem., xxxiv, 1886, p. 177. 



