OZONE AND ANTOZONE. © £33 
by ozone. <A crystal of the former salt placed in an ozone atmosphere be- 
comes gradually red, the color proceeding from the outside to the inside, and 
the solution of ferrocyanide of potassium experiences this change very readily 
when agitated with ozone. 
The metals arsenic, antimony, iron, zine, tin, lead, bismuth, silver, and mer- 
cury, are oxidized instantly by ozone, and deprive thereby any atmosphere con- 
taining that gas. 
The metals are not oxidized with equal facility. Thus arsenic is oxidized 
much more readily than antimony, which affords an additional means of dis- 
tinguishing between these bodies in judicial inquiries. An arsenic spot ina 
strong ozone atmosphere is converted instantly to arsenic acid, while an anti- 
mony mirror requires several days for its disappearance. Dry mercury, or that 
covered with water, does not absorb ozone; if the metal be merely moistened, 
it takes up ozone readily, becoming yellowish upon the surface. 
Silver, in the state of leaf or sponge, absorbs ozone quickly, as has been 
stated already. This metal may be employed for separating ozone from ordi- 
nary oxygen. 
The more readily oxidized metals, as protoxides of manganese, iron, tin, &c., 
as well as those which, like protoxides of silver and lead, are not so easily 
changed to a higher state of oxidation, are peroxidized by ozone. 
A solution of the sulphate of the protoxide of manganese is browned in- 
stantly in ozone from the above cause, and, according to Schoenbein, this reac- 
tion is perceptible in a dilute solution of sulphate of zinc, which contains as 
an impurity only ;,5,5 of manganese. If hydrated oxide of lead be spread 
upon paper, or if basic acetate of lead be employed, ozone will communicate 
to the paper first a yellow, then a red, and finally a brown coloration from the 
peroxidation. . 
If the lead paper be blackened by means of sulphide of hydrogen, it may 
be bleached in ozone, which is due to the production of the white sulphate of 
lead. 
Organic bodies are very readily oxidixed in ozone, as shown by the experi- 
ments of Schoenbein, Baumert, Gorup von Besanez, &c. Thus wood, straw, 
cork, starch, humus, vegetable colors, caoutchouc—pure and vulcanized—the 
fats and fatty acids, alcohol, albumen, blood, &c., have been found to be all 
acted upon by this agent. Ozone bleaches litmus without first reddening it. 
Certain fungi become blue in:the air, and the cut surface of an apple becomes 
brown by the action of ozone. 
Gum guiacum, which becomes gradually blue in the air, owes this change to 
ozone, as was first shown by Schoenbein, who employed this substance as a 
reagent for ozone. ‘To prepare guiacum papers, one part of the gum is dis- 
solved in thirty parts of 90 per cent. alcohol. One gramme of ordinary alco- 
hol is charged with a few drops of this solution, and the paper slips are dipped 
therein and dried. ‘he papers are blued rapidly in an ozone atmosphere. 
‘They lose this color when exposed to the air, but regain it in ozone, and the 
process may be repeated until the guiacum is fully oxidized. Certain metals 
and other bodies, especially nitrous acid, chlorine, bromine, peroxides of man- 
ganese, and lead, &c., will blue guiacum tincture. 
The following is Schoenbein’s method of determining ozone quantitatively 
in a mixture from its bleaching effect upon the solution of indigo: The ordi- 
nary solution is diluted with sufficient water to be just opaque blue. One hun- 
dred grammes of this solution receive an equal weight of hydrochloric acid, 
and are then boiled. The heated liquid is treated with a solution containing 
xia of chlorate of potassa until the blue color is exchanged for a brownish 
yellow. If, now, for the destruction of the 100 grammes of indigo solution, 
100 milligrammes of chlorate of potassa (which contain 39 milligrammes 
