1873.] Mixture of Air and Steam upon Cold Surfaces. 



279 



Table III. 

 A = 748, * =11, 7=500. 



a. 





1 



Drops per 

 minute. 



ii 



JT2. 





i>2. 



.Drops 



Ps 







6 



741 



■ 



7 







7 













47 



663 



106 



85 







85 



•o 



125 



*3-2 



66 



557 



106 



191 



6 



185 



•032 



60 



5 



>> 



»> 



56 





9 



182 



•050 



30 



10 



>j 





2L 



> j 



18 



173 



•104 



11 



15 



>> 



>» 



17 



J! 



27 



164 



•163 



10 



20 



J> 





12 





36 



155 



•23 



8 



30 



»| 



552 



10 



196 



54 



142 



•39 



7 



40 





557 



8 



191 



72 



119 



•60 



6| 



50 



J> 



562 



7 



186 



90 



96 



•93 



7 



12. Table I. shows the result of an experiment after the first method, 

 during which the flame and condensation remained constant, whilst the 

 pressure within the flask increased with the quantity of air. 



Table II. shows the result of an experiment after the second method, 

 in which the pressure within the flask remained constant, whilst the flame 

 and condensation were reduced as the air was admitted. In this experi- 

 ment the rate at which the water passed through the condenser was 

 constant from first to last, and consequently the temperature of the 

 effluent water varied with the condensation. 



Table III. shows the result of an experiment, also made according to 

 the second method, but in which the quantity of water flowiug through 

 the condenser was so varied that the temperature of the effluent water 

 remained constant. 



13. Each of these Tables shows the effect of air on the condensation in 

 a very definite manner ; but the results as given in the column jp 3 in 



Drops 



~¥* 



stand ; for these show the effect of the air in a series of increasiug figures. 

 If, however, these figures show the power of the air to diminish conden- 

 sation, then they will be inversely proportional to the quantity of water 

 condensed, i. e. what would have been condensed if the pressure and 

 other things had remained constant. Hence the numbers in the column 



— should be proportional to the numbers in the column — in Tables 



H. and III. 



In order to compare the results of these experiments, the results in each 

 Table have been multiplied by a common factor, so that they may be the 

 same when the pressure of air is one tenth that of the steam. Thus the 



numbers in the column i in Table I. have been multiplied by 2000, and 

 Drous 



numbers under in Table II. by 7. The result of the experiments thus 

 reduced are shown in the curves 1, 2, 3. 



Table I. cannot be compared with the 



in Tables II. and III. as they 



