556 
streaks. The figure on that part of the ozone scale which corresponds in tone 
with the color of the test paper, is entered in the records for the observation. If 
there is no discoloration of the test paper, no ozone is present, and a cipher is 
entered on the record for that observation. 
PROPERTIES OF OZONE. 
Ozone is an intensely oxidizing agent, capable of effecting at ordinary tem¬ 
peratures chemical changes of which ordinary oxygen is utterly incapable. It 
oxidizes all the metals except gold and the platinum group. Even silver is oxi¬ 
dized by it. It instantly burns phosphuretted hydrogen; oxidizes and destroys 
sulphuretted hydrogen; oxidizes hydrochloric acid, rendering it capable of dis¬ 
solving gold leaf; oxidizes iodide of potassium, setting free the iodine and form¬ 
ing caustic potash. I also find that ozone will readily decompose bromides, set¬ 
ting free bromide, as is shown by the reaction with gelatinized starch. This reac¬ 
tion with starch is very brief, but the odor of the liberated bromide is very strong. 
Persons at the seaside often observe a strong “cholorous smelT’ from sea water. 
It is much more probable that the odor is bromous^’^ from decomposition of 
bromides in sea water by ozone, which is often so abundant by the sea. 
I find also, a fact not before observed so far as I am aware, that ozone will, 
at ordinary temperatures, oxidize the deadly carbonic oxide into the compara¬ 
tively innocent carbonic dioxide or carbonic acid. Carbonic oxide is one of the 
most deadly gasses known. Unlike sulphuretted hydrogen, phosphuretted hydro¬ 
gen, and ammonia of animal origin, it gives no warning of its presence by its 
odor or other sensible property. The power of ozone to oxidize this deadly gas 
at ordinary temperatures is a fact of prime importance in preserving the purity of 
our atmosphere. It has been a question in my mind whether carbonic oxide is 
not given off with other materials in the mixed gases which escape from decopos- 
ing organic matter in swamps, and is not one potent factor in miasm ? May not 
the rapid disappearance of the red globules, and consequent anaemic appearance 
so often produced by miasmatic diseases be caused by the well known power of 
carbonic oxide to destroy the red globules? I have had no opportunity to inves¬ 
tigate this subject, but I throw out the suggestion for your consideration. But 
whatever the nature of miasm or malaria, the power of ozone to oxidize carbonic 
oxide to carbonic acid at ordinary temperatures can not be an unimportant factor 
in preserving the purity of the air. 
Ozone will oxidize ammonia into nitrate of ammonia, and will, in particular, 
oxidize the ammoniacal compounds which are produced by the decomposition 
of azotized organic matter. This power of ozone to oxidize the hydrogen 
compounds of sulphur, phosphorus, and nitrogen, enables it to destroy the offen¬ 
sive products of animal decomposition. Thus it will instantly destroy the horri¬ 
ble smell of rotten eggs. Schonbein found that air made foul by exposure for 
one minute to four ounces of highly putrid meat, was disinfected by an equal 
volume of air containing only one part of ozone in 3,240,000 parts of air. Ozone 
Missouri Botanical Garden 
George Engelmann Papers 
/ 
THE SCIENTIFIC MONTHLY. 
Botanical 
copyright reserved garden 
