196 ANNUAL OF SCIENTIFIC DISCOVERY. 



and placed one in the open air, and the other in a room badly 

 ventilated and well filled with company. After the expiration of 

 a certain time, he had them both brought to him, and ascertained 

 that the first emitted a distinct odor similar to that of ozone, while 

 the second was completely inodorous. Fresh air in its normal state 

 is endowed with decided powers of decoloration. Litmus and 

 turmeric paper, exposed to its influence and sheltered from the 

 effects of rain, dew, and sunlight, are blanched in a short time, 

 demonstrating that ozone acts energetically as a decolorizing 

 agent. It has long been known as a powerful disinfectant, and, 

 could means be devised for procuring it in a free state, it would 

 be of the greatest advantage in purifying vitiated atmospheres.— 

 Comptes Bendus, March, 1868. 



Dr. Thomas Andrews made the following communication to the 

 Royal Society : — 



*' It was assumed for many years, chiefly on the autliority of 

 Schonbein, that the body in the aUuosphere which colors iodide of 

 potassium paper is identical with ozone ; but this identity has of 

 late been called in question, and, as the subject is one of consider- 

 able importance, I submitted it lately to a careful investigation, 

 the results of wliich I beg to lay briefly before the soeiet3^ The 

 only property of ozone, hitherto recognized as belonging to the 

 body in the atmosphere, is that of setting free the iodine in iodide 

 of potassium ; but as other substances, such as nitric acid and 

 chlorine, which ma}^ possibly exist in the atmosphere, have the 

 same property, no certain conclusion can be drawn from this fact 

 alone. 



♦'One of the most striking properties of ozone is its power of 

 oxidizing mercury, and few experiments are more striking than 

 that of allowing some bubbles of electrolytic oxygen to play over 

 the surface of 1 or 2 pounds of mercury. The metal instantly loses 

 its lustre, its mobility, and its convexity of surface, and, when 

 moved about, it adheres in thin mirror-like films to the sides of the 

 containing glass vessel. The body in the atmosphere acts in the 

 same way upon pure mercury ; but from the very minute quantity 

 of it which is at any time present, the experiment requires some 

 care in order that the effect may be observed. On passing a 

 stream of atmospheric air, which gave the usual reaction with test- 

 paper, for some hours over the surface of mercury in a U-tube, the 

 metal was distinctly oxidized at the end at which the air first came 

 into contact with it. 



"This experiment, however, cannot be considered conclusive, 

 as mercury will tarnish and lose its mobility under the influence 

 of many bodies besides ozone. 



** It is well known that all ozone reactions disappear when ozone 

 is passed through a tube containing pellets of dry peroxide of 

 manganese, or other body of the same class. The same thing 

 occurs with the substance supposed to be ozone in the atmosphere. 

 About 80 litres of atmospheric air were drawn, at a uniform rate, 

 through a tube containing peroxide of manganese, and afterward 

 made to play upon very delicate test-paper. Not the slightest 

 coloration occurred, although the same paper was distinctly 



