WITH WHICH AIR RUSHES INTO A VACUUM. 



163 



With the object of giving more completeness to this 

 research, experiments were made to ascertain through 

 what range of relative densities the air in two vessels 

 would act as a vacuum to the other for pressures below 

 that of the atmosphere. The results are shown in Table 

 VI,, which are arranged in the same manner as those in 

 Table V. The times in the second vertical column are 

 taken from those shown in Table II. Avhen the discharge 

 was made into a vacuum for each pound of pressure, and 

 the other times in the Table are those obtained for suc- 

 cessive discharges into air of different densities below the 

 atmosphere, the larger cylinder being again used as a 

 receiver. 



Table VI. 



Pounds 























per 

 square 

 inch. 







I 



2 



4 



6 



8 



10 



12 



2I-S 



14 





15 



i6"o 



i6"o 



16 



160 



1 6-^0 



i6-s 



i8-o 



3r'i 



seconds. 



14 



i7'5 



17-5 



17-5 



17-5 



i7"5 



i8-5 



20-5 



26'5 







12 



21-0 



ZI'O 



21'0 



ai'o 



2I-0 



22-<; 



3O'0 









10 



25-5 



25-5 



25-5 



25'5 



26-5 



33-5 











8 



32-5 



32-5 



32-5 



32-5 



38 













6 



45-0 



45-0 



45-0 



47.5 















4 



70-0 



70-0 



72'0 

















2 



liio-o 



190-0 



















As equality in the times indicates equality in the quan- 

 tities and velocities of the discharge for constant pressures, 

 a simple inspection of the Table shows that, for discharg- 

 ing pressures as low as 6 lb., the recipient air still acts as 

 a vacuum up to half the density of the discharging stream, 

 and the regularity of this law is maintained within the 

 limits of 6 lb. and 90 lb. absolute pressure, as shown in 

 Table V. For discharging pressures below 6 lb. the rela- 

 tive times of discharge and the resistance of the recipient 

 air increase ; and as we have already s?en that the similar 



m2 



