160 On Ozone and tts Relations to 
constant usage. I have known instances where animal 
charcoal has oxidysed 262 grains of organic matter requir- 
ing forty-five grains of oxygen inan average of 150 gallons 
of : water per day, for nine, and twelve months consecutively, 
supplying it with three-tenths of a grain per gallon of 
gaseous oxygen without in any way having been exposed 
to atmospheric air. In more than one example, moreover, 
the charcoal was immersed in three feet of water, and the 
surface of such water was exposed to the open air and 
sunlight each day, circumstances favourable for speedily 
depriving it of any air it might naturally contain. 
As, to the source of ozone to furnish such oxidizable 
matter present in solution. It is uncertain whether it is 
obtained from the actual organic matter, or whether the 
mineral salts coexistent with it, take an active part in fur- 
nishing this element. If distilled water, after considerable 
exposure to the open air, be treated with the ozone test, 
no indication of ozone will be found to be present. If, on the 
other hand, water, containing salts of lime, &c., be treated 
in the same manner,a very different result will ensue. 
The water seemingly increasing in its capacity for ozone in 
proportion to the quantity of salts present. As might ‘be 
reasonably anticipated, the least stable salt thus containing 
the oxygen necessary for furnishing the ozone, would be 
found to be affected after the process. Such actually takes 
place in practice by filtration. The carbonate of lime held 
as bicarbonate in solution is lessened often to the extent of 
two grains per gallon. Still more conclusive is the fact 
that a second filtration immediately afterwards does not 
reduce the salts. As a negative instance also of the direct 
virtue of these auxillary salts, “ rain-water” containing as 
it invariably does, organic matter, is found to be far more 
difficult to purify than water containing with it the av 
quantity of inorganic salts. 
Such is the action of animal charcoal or soluble organic 
matter that, if the organism is perfect and the affinities 
balanced, no reaction is perceptible. If, on the other hand, 
the forces of attraction are in a partial state of resolution, 
the animal charcoal taking to itself the oxygen of the com- 
pound, redistributes it into more simple and stable com- 
pounds. A subsequent analysis is found to yield a less 
oxidizable organic residue, slightly lessened by the amount 
of water and volatile gas, the product of the recombination. 
To the chemical analyst it is a familiar circumstance to 
meet with certain substances combining with each other 
