130 KANSAS ACADEMY OF SCIENCE. 



sent to Chicago and Denver for assay. One of the certificates, in my 

 possession, from the Chicago and Aurora Smelting and Refining Com- 

 pany, reports a value in gold of thirty-two dollars, and silver twenty- 

 five cents, per ton. Baker's find was about seven years ago, and 

 attracted considerable comment. 



More or less scientific investigations ensued, and from that date 

 until now very different conclusions have been reached. Assayers 

 from the Atlantic to the Pacific have tested these shales: Many 

 of them have reported absolutely no trace of gold. This class agree 

 in results. From the rest of the tests, which vary all the way from 

 traces up to fine values of gold and silver, worth as much as fifty dol- 

 lars per ton. These persons do not agree with each other to any 

 marked extent, and often the same assayer will find very discordant 

 returns from the same specimen. What shall we conclude from such 

 testimony? 



In the first place, considering the sedimentary deposit where gold 

 is found, there is a probability that it may contain anything that 

 is found in sea- water. From several tests, I have found that the dry 

 shale will lose about nine per cent, when heated for some time to 350 

 degrees centigrade. The volatile matters given off were water vapor 

 (of crystallization) and petroleum-like substances. When heated to 

 redness, I obtained vapors of zinc oxide. 



Without undertaking to determine how the gold got into the shale, 

 whether by precipitation from the sea- water or by alluvial deposit, it 

 is certainly in a very fine state of division. When the shale is pulver- 

 ized to 100 mesh and carefully washed with water, a residue is found 

 which, under the microscope, shows grains of silica and pyrite and 

 some grains of gold. Some residue yields a quantity of gold on assay, 

 which shows that plain washing with water will produce considerable 

 concentration of values. In the washing process, it is likely that we 

 lose some of the very finely divided gold. 



In my investigation of this shale, many modes of assay have been 

 tried. The ore has been roasted with various kinds of fluxes before 

 assay, and in a good many cases this preliminary treatment has been 

 useful. In the spring of 1899, cooperating with Doctor Franklin, at 

 Lawrence, we made over 100 assays of shale, which had been obtained 

 from a number of different places. Many of our results were blanks, 

 but a few showed small values in gold. In the following summer — that 

 is, two years ago last summer — I went to the Smoky valley and took 

 shale from many places up and down the river for several miles. I 

 brought my specimens to Topeka and worked on them for a month, 

 making over 100 assays. This gave small values, the last twenty av- 

 eraging about one dollar to tlie ton. In these two series of assays, the 



