Davis.] 108 (April 6, 
lost all power in converting the chlorine or depositing the gold. Although 
the coal in the large filter from which this portion was taken, retained its 
full power for three succeeding days, and, so far as the eye could judge its 
character as a charcoal, remained unchanged ; whilst the portion subjected 
to 80° hid lost all characteristics of charcoal in qualities and appearance. 
Pressing occupations interfered with a further examination of this method 
of reducing charcoal to a soluble condition. This is presented as a new 
and interesting feature in the history of chlorine. ‘ 
From notes of a laboratory experiment in a qualitative examination, the 
following details are given as illustrative of the methods employed to ar- 
rive at reliable results. The novelty of the subject and the importance 
of the conclusions, are offered as apology for the minuteness of detail ; 
A. glass percolator, 18 inches deep, was filled with granular wood char- 
coal, without other preparation than expelling enclosed gases, and re- 
moving adhering substances by immersion in water; a gum tube and 
compressor at the outlet served to regulate the flow ; twenty-four ounces 
of coal were employed ; 100 gallons of solution were used, carrying chlo- 
rine that was evident to the senses in escaping fumes ; inhalation could 
not be made at the surface of the coal. This represented 750 pounds of 
an ore assaying $15.65 gold to the ton. Temperature of the room about 
75° F., density of the liquid 3.75 Beaumé; the rate of flow was regulated 
to one gallon per hour, and continued uninterrupted until the close of the 
experiment, or 100 hours. 
At intervals of an hour samples of the escaping fluid were taken, and 
tested for gold with sulphate of iron, in every instance it failed to detect 
gold. 
The rich blue color of the escaping liquid showed the presence of cop- 
per; remembering that the presence of copper had hitherto impaired the 
action of sulphate of iron as a precipitant, it remained to be shown. that. 
the want of precipitate in the test tubes was a reliable indication of the 
absence of gold; to test this, every tenth gallon of the filtrate was sub- 
jected to the following treatment : 
The copper was precipitated by clean iron wire, the resulting cement 
copper washed on a filter, then dissolved by SO%, and the undissolved por- 
tions secured on a filter, dried, and incinerated, and the ash assayed for 
gold; the return of which was .01 grain. Now as one gallon represented 
the y}, part of a ton of ore, the above result shows a loss by reason of the 
presence of copper of 2.66 grains of gold per ton == 114 ets. 
At the conclusion of the flow, the charcoal was washed, carefully incin- 
erated in an iron dish, and the ash smelted with borax. The button of 
gold weighed 1389 grains, as the return from 750 lbs. of ore ; which is equal 
HOB Bre QAR CM wale nian ve van Nae ew vaeh BLUNT EDO CORN 
sea VAN OL DONS! vacane Ke piel |idacely dy Mama MitneieNnMEN MORCOIE SIN 
A difference of 12 cents per ton in favor of the finer determinations of 
analysis by solution, over the approximative method of smelting by fire 
assay. 
