of Determining Moisture and Carbonic Acid in Air, 321 



Experiment No. 4. 

 50 litres aspirated at a rate of If litres per minute. 

 Soda-lime, pair 1 . . +0*0558. 

 . +0*0001. 



,, pair 1 



„ 2 



Experiment No. 5. 

 21 litres aspirated at a rate of 2 litres per minute. 

 Soda-lime, pair 1 . . + 0*0339. 

 „ „ 2 . . +0*0003. 



Experiment No. 6. 



In this experiment commercial soda-lime (Hopkins and 

 Williams) was used. 



The soda-lime contained much more water than ours, as 

 shown by its appearance and the amount of water it gave up 

 to dry air. 50 litres aspirated at a rate of 1 litre per minute. 



Soda-lime, tube 1 . . . . — 0*0552\ , 



Sulphuric acid, tube 3 . . + 0*0923/ to g ether +0*0371. 



Soda-lime, pair 2 . . . . +0*0000. 



Experiment No. 7. 



The same soda-lime tube was used as in the previous 

 experiment. 50 litres aspirated at a rate of 2 litres per 

 minute. 



Soda-lime, tube 1 . . . . -0*0478\ 

 Sulphuric acid, tube 3 . . + 0*0893 J + U ' U415 - 

 Soda-lime, pair 2 . . . . +0*0013. 



A rate of 1 litre a minute is thus well within the limit of 

 safety, so that even should the aspiration be temporarily 

 faster, there is no risk of appreciable non-absorption of either 

 moisture or carbonic acid. 



The number of analyses possible without refilling the 

 carbonic-acid tubes was determined in the same way as for 

 the moisture-tubes, i. e. by passing air through two pairs at a 

 rate of 1 litre per minute, and weighing the second tube at 

 intervals. 



Experiment No. 8. 



120 litres of air had already been passed through pair No. 1. 



Litres of air aspirated Variation in weight 



through pair 1. of pair 2. 



235 +0*0003 



354 -0*0001 



418 +0*0010 



568 +0*0049 



