﻿418 Mr. H. Pealing on Condensation Nuclei 



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filters of combustion-glass, which could always be cleansed by 

 being heated to redness, while glass-wool or cotton-w r ool 

 niters, which are generally used finally to free a current of 

 purified air from dust, have just the opposite effect, and 

 charge the air again with all the impurities which have been 

 previously removed, thus vitiating the results." 



In reply to these objections, I would point out that his 

 conclusions rest upon the assumptions that ozone is produced 

 by the interaction of iodine and water, viz. 



H 2 + I — HI + HIO, 



HIO + 0,-*-HI + 8 . 



So far as I am aware no proof exists that this chemical 



action goes on under the conditions of our experiments. 



(Ramsauer's reference to our experiments establishing that 



fact is a mistake.) What evidence there was, negatived that 



conclusion. If such an action goes on, then the water should 



become acid, but it was found that it was of the same degree 



of acidity after several days' exposure to the iodine as it was 



before its introduction to the apparatus. But Ramsauer's 



explanation seems to break down much more completely 



when we consider the reappearance of the effect on washing 



the apparatus. Experiments showed that the introduction 



of water into the apparatus up to about 100 cc. in amount 



had no appreciable result on the effect so long as the surface 



of the glass was not rinsed in the process. Hence, if 



Ramsauer's explanation is correct, the amount of water 



necessary to introduce sufficient impurity to bring back the 



effect must be of the order of many kilograms. That is, the 



apparatus must be rinsed with several kilograms of water 



before the glass walls are saturated with the minor impurities 



he mentions, and the iodine effect would continue until all 



these impurities were exhausted. It may be urged that only 



a small part of the impurity contained in that amount of 



water is absorbed by the glass. It is very unlikely that this 



is the case with the water contained in the apparatus (of the 



amount of 200 grms. approximately). Now in a case like 



this the effect is very much smaller on the second day after 



the introduction of the iodine, and by the fourth day has 



entirely disappeared. That is, on Ramsauer's theory the 



impurity necessary to keep the effect going at an appreciable 



rate for two days is contained in an amount of water which 



cannot be more than 200 grams. Now when we come to 



consider the case of the glass-wool, we find that when so 



