ACADEMY OF NATURAL SCIENCES. 379 



num. gold and silver. It is only in portions containing dolomite and the pecu- 

 liar greenish mineral, so characteristic of the mother lode, that lime, magnesia, 

 alumina, and chromium are detected. In portions of the fahlerz-like mineral 

 which appear nearly pure, the blowpipe detects only antimony, arsenic, copper, 

 iron, and manganese. 



Having transmitted characteristic specimens of these ores, with other inter- 

 esting California species, to Professors Dana and Brush, at New Haven, these 

 mineralogists inform me, by letter just received, that the tellurids above-named 

 appear to be referable to a new species hitherto undescribed, and Prof. Brush 

 proposes to undertake an analysis of it upon the specimens transmitted by me, 

 which are barely sufficient for the purpose. It is a tellurid of silver and gold, 

 containing more silver than gold. Associated with it is a white cleavable 

 mineral which Prof. Brush thinks may prove to be native tellurium ; this is in 

 the Melones and Golden Rule specimens. 



Hessite. I obtained from the Reist Mine, on the northeasterly end of Whisky 

 Hill, Tuolumne County, a very small crystal corresponding in its physical char- 

 acters to the extremely rare telluric silver, known to mineralogists as Hessite. 

 It occurs in the auriferous slates to the east of the main vein ; the slates being 

 opened here for a width of seventy-five feet as an open cut. My attention was 

 called to the existence of this species at the Reist Mine by Mr. D. T. Hughes, 

 of Tuolumne County, who informed me that there was an interesting mineral 

 species there containing, as he believed, tellurium, and that masses of it, half an 

 ounce in weight, had been obtained some years since. Unfortunately these 

 specimens fell into ignorant hands, and were destroyed in idle attempts to deter- 

 mine the nature of the substance. On visiting the locality, which is within one 

 mile of the Rawhide Rancho, and on the opposite side of Table Mountain, I 

 found that the proprietor was exploring in a different part of the open cut from 

 that where this species was found, the place being under water. Fortunately in 

 a collection of minerals from Whisky Hill, formed by Mr. Williams, one of the 

 proprietors, and preserved in his house there, I was able to detect one small 

 mass of the Hessite which "Mr. Williams divided with me. This Mr. Hughes 

 recognized as identical with the larger masses he had obtained at this mine some 

 years since. 



Prof. Bush, in his letter to Prof. Silliman, of October 29th, recognizes this 

 species as Hessite. The specimen was associated with native gold which had 

 been amalgamated and heated, but the constitution of the Hessite did not seem 

 to be affected thereby. 



" Tellurid of Silver " is mentioned by Blake, in his list of California species, as 

 found by him near Georgetown, in El Dorado County, in 1854, washed from the 

 gold drift, but the parent vein had never been found. — Ross Browne's Report, 

 1867, p. 209. 



It appears therefore, from the present state of our knowledge, that a com- 

 pound of gold and silver tellurium belonging probably to a new species has been 

 detected in three localities upon the mother vein, and associated with it in two 

 of these, probably also native tellurium ; and that Hessite (the tellurid of silver) 

 has been found in place in one locality and in the drift in another. I have also 



