354 PLEASANT WA YS IN SCIENCE. 



wide-mouthed bottle. The blood had then coagulated, and 

 it was left exposed to the air until it had become entirely 

 redissolved by the effects of decomposition. At the end of 

 a year the blood was put into a stoppered bottle, and set 

 aside for seven years. " The bottle was then taken from its 

 hiding-place," says Dr. Richardson, " and an ounce of the 

 blood was withdrawn. The fluid was so offensive as to pro- 

 duce nausea when the gases evolved from it were inhaled. 

 It was subjected by Dr. Wood and myself to a current of 

 ozone. For a few minutes the odour of ozone was destroyed 

 by the odour of the gases from the blood ; gradually the 

 offensive smell passed away; then the fluid mass became 

 quite sweet, and at last a faint odour of ozone was detected, 

 whereupon the current was stopped. The blood was thus 

 entirely deodorized ; but another and most singular pheno- 

 menon was observed. The dead blood coagulated as the 

 products of decomposition were removed, and this so per- 

 fectly, that from the new clot that was formed serum exuded. 

 Before the experiment commenced, I had predicted on 

 theoretical grounds that secondary coagulation would follow 

 on purification; and this experiment, as well as several 

 others afterwards performed, verified the truth of the pre- 

 diction." 



It will of course be understood that ozone, in thus acting 

 as a disinfectant, is transformed into oxygen. It parts with 

 its third atom as in the mercury experiment, and so loses 

 its distinctive peculiarity. Thus we might be led to antici- 

 pate the results which come next to be considered. 



Ozone has certain work to do, and in doing that work 

 is transmuted into oxygen. It follows, then, that where 

 there has been much work for ozone to do, there we shall 

 find little ozone left in the air. Hence, in open spaces where 

 there is little decomposing matter, we should expect to find 

 more ozone than in towns or cities. This accords with what 

 is actually observed. And not only is it found that country 

 air contains more ozone than town air, but it is found that 

 air which has come from the sea has more ozone than even 



