544 On the Velocity with which Air rushes into a Vacuum. 



resistance of the recipient atmospheres would be still further 

 diminished correlatively with an increase in the amount of 

 discharge. 



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. when 

 the discharge was made into a vacuum for each pound of 

 pressure, and the other times in the Table are those obtained 

 for successive discharges into air of different densities below 

 the atmosphere, the large cylinder being again used as a 

 receiver. 



Table VI. 



Pounds 























per 







1 



2 



4 



6 



8 



10 



]2 



14 





square 























inch. 















180 









15 



160 



160 



160 



16-0 



16-0 



16-5 



21-5 



355 



seconds. 



14 



17'5 



17-5 



17-5 



175 



175 



18-5 



20-5 



26-5 





>> 



12 



21-0 



210 



21-0 



210 



21-0 



225 



30-0 









10 



25-5 



25-5 



25-5 



25*5 



26-5 



33-5 











8 



32-5 



325 



32-5 



325 



38-0 











j> 



6 



450 



450 



45-0 



475 













jj 



4 



700 



70-0 



720 















5) 



2 



1800 



190-0 

















)5 



As equality in the times indicates equality in the quantities 

 and velocities of the discharge for constant pressures, a simple 

 inspection of the table shows that, for discharging 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 relative times of discharge and the 

 resistance of the recipient air increase ; and as we have already 

 seen that the similar times and resistances for discharging 

 pressures above six atmospheres diminish, the continuity of 

 regular law is broken at both ends of the series of pressures, 

 just as it is in the series of planetary distances and some other 

 quantitative phenomena of nature. 



