170 OZONE AND ANTOZONE. 
exposed to the dark rays of the spectrum, unite, with explosion, and yield 
ordinary oxygen. 
Schoenbein considers that oxygen undergoes chemical polarization in the 
body when respired, and accounts thus for the rapid changes which take place 
in the tissues. He has found peroxide of hydrogen in the urine, and has dis- 
covered that the blood corpuscules instantly decompose this compound. Ie 
has given the following test for the peroxide of hydrogen. ‘To water, supposed 
to contain the peroxide, he adds one or two drops of a solution of a salt of 
bismuth, nickel, cobalt, thallium, &c., and then just enough of potassa to pre- 
cipitate the hydrated oxide of the metal. He then adds a little iodide of po- 
tassium and starch, and lastly one or two drops of acetic or dilute sulphuric 
acid. If the merest trace of peroxide of hydrogen be present, the liquid is 
instantly colored blue. 
The following is Schoenbein’s method of determining quantitatively the de- 
composition of oxygen into ozone and antozone. During the slow oxidation 
of metals, according to this chemist, the oxygen is chemically polarized; one 
of its atoms (ozone) unites with the metal or oxidizable matter, while the other 
atom (antozone) combines with water to form peroxide of hydrogen. Schoen- 
bein agitates an amalgam containing five per cent. of lead, with very dilute 
sulphuric acid of known strength, in a large bottle partially filled with air or 
oxygen. After a few moments of agitation, a quantity of sulphate of lead is 
produced, and peroxide of hydrogen is found in the acidulated water. He 
ascertains the oxygen which has combined with the lead, by determining the 
amount of uncombined acid, thus calculating the sulphate of lead formed, and 
consequently its oxygen. He determines the peroxide of hydrogen in another 
portion of the water by a standard solution of permanganate of potassa, and 
finds the quantity of oxygen in this peroxide to be very nearly the same as 
that contained in the oxide of lead. , 
Different chemists have determined the diminution of volume experienced by 
air or oxygen during ozonization. 
Andrews and Tait placed pure dry oxygen ina tube and discharged elec- 
tricity through the gas. With still discharges a diminution took place, which 
was at first rapid and then slow until a maximum was reached, yielding a 
diminution equal to 4, of the original volume. When, now, a few sparks were 
passed through the gas it expauded 3 of the former diminution, but did not 
attain its original volume. With rapid or spark discharges, oxygen experiences 
a, diminution of volume, although less than by still discharges. Oxygen, con- 
tracted by the formation of ozone, when left to itself at the ordinary tempera- 
ture, expands again gradually. At 100° Centigrade it expands more rapidly, 
and at 270° it regains its original volume and loses all of the characteristics of 
ozone. At this temperature, therefore, ozone is destroyed. Andrews and 
Tait found that, by still discharges, oxygen cannot lose more than +5 of its 
volume, unless the ozone be removed as fast as it is generated, in which case 
the diminution may proceed indefinitely. ‘They determined 60 for the density 
of ozone compared with oxygen, which makes it six times lighter than lithium. 
They were unable to condense it to a liquid at ordinary pressures by a freezing 
mixture of solid carbonie acid and ether. , 
Ozone may be prepared for examination most readily by dropping, in small 
quantities, dry permanganate of potassa in a bottle containing a little oil of 
vitriol, or by placing a stick of phosphorus, scraped clean under Water, in 
the bottom of a capacious vessel containing enough lukewarm water to half 
submerge the phosphorus. In either of these cases a slip of iodide of potas- 
sium starch-paper becomes instantly blue when immersed in the air of the ves- 
sel, and the different ozone reactions may be readily perceived by employing 
the appropriate tests. ‘The gas may also be investigated with the above starch- 
paper in the neighborhood of a point upon the prime conductor of an elee- 
