A, A. Hayes on the Cochituate Water. 259 
The general supply of water to a populous city, had thus be- 
come very offensive, without any adequate cause appearing, and 
the evil led to the expression of many hypotheses and supposi- 
tions, chiefly without reliable support. . 
As the subject was one within the reach of experiment, the 
course adopted was the following: A displacement apparatus of 
glass, was charged with recently calcined animal charcoal, of me- 
dium fineness; over this was placed a conical filter of clean cotton, 
so that any water, falling on the charcoal, would first pass through 
the cotton filter. The water from a contracted ‘supply pipe, was 
allowed to flow slowly on the cotton filter, and passed away, so 
long as the pores remained open. Removing the cotton filter, 
the charcoal was allowed to drain, the water displaced by alcohol, 
and the alcohol by sulphuric ether, without removing the coal. 
Some oil was found in the alcoholic fluid, while the aqueous 
— was colored by it, from a tint of yellow to a light olive 
color, ; 
By evaporation at 90° to 100°, the ether left some globules of 
fluid oil, but by far the larger bulk of residue, was a soft solid in 
granules, without crystalline form. By warming the solid with a 
little acid, a base was dissolved, generally lime, or lime-and ammo- 
nia, While the oil floated on the fluid, and was left by evaporation 
of the water. As thus obtained, this oil was of a light yellow 
color, Presenting both oleic and stearic acids. Its specific gravity 
as the same as that of lard oil. Alcohol dissolved it without resi- 
ue. A solution of carbonate of soda saponified it when warmed, 
Proving the acid condition of the oil. With sulphuric acid it 
blackened, and chlorine changed its color to dark brown. 
: he oil, as separated from the etherial solution, in different ex- 
periments, assumed a solid state at 80° or 90° F. Acids elimin- 
ated oily fluids constantly, with the emission of a peculiar odor. 
teated with carbonate of soda, when the soap was decomposed, 
an odor resembling that from adipocere was generally percepti- 
ble. When the charcoal, while wet from the water, was distil- 
—t0 its more near| y normal state. At one time, twenty-eight vol- 
umes of water evolved by boiling, one volume of gases. ‘Twen- 
ty-five volumes of the gases were diminished only one volume, by 
P hosphorus, warmed and left twenty-four hours ; or about four 
