MODIFIED BY THE DISCHARGING OKIFICE. 



185 



errors of observation and experiment^ and the mean value 

 of the coefficient for all the pressures is '937. 



Applying this coefficient to the velocity deduced in 

 Table I. of my former paper for an orifice in a thin plate, 

 we have for the maximum velocity with which air of 

 135 lbs. pressure rushes into a vacuum, before expansion, 



V= ■^-^— =800 feet per second. 

 •937 



Some anomalous rates of effiux from the same orifice 

 which were obtained when air of less than 15 lbs. effective 

 pressure was discharged into the atmosphere, induced me 

 to make a series of experiments on the discharge of air of 

 an initial pressure of 15 lbs. through the same orifices as 

 in the last experiments, and the times were recorded for 

 each reduction of 2 lbs. of pressure. 



All the discharges were made with the conoidal orifices 

 inside the vessel, but they were also made through C and 

 D with these orifices outside the vessel. The results are 

 shown in the following Table : — 



Table II. — Discharge into the Atmosphere. 



Lbs. 





















per 



Orifice 



Plain 



Conoidal 



Conoidal 



Conoidal 



Conoidal 



Conoidal 



Double 



Coeffi- 



square 

 inch 

 effec- 



in 

 thin 



plate. 



tube 



orifice 



orifice 



orifice 



orifice 



orifice 



couoidal 



cients 



for 

 orifice. 



orifice. 



inside. 



inside. 



outside. 



inside. 



outside. 



orifice. 



tive 





















pres- 







A 



B 



C 



C 



D 



D 



E 







sure. 























sec. 



sec. 



sec. 



sec. 



sec. 



sec. 



sec. 



sec. 





15 



i6'o 



13-5 



i4"o 



14*0 



14-0 



14-5 



14-5 



15-0 





829 



13 



17-5 



14-5 



15-0 



15-0 



15-0 



.6-5 



160 



1 6-0 





829 



II 



i9'5 



i6-o 



i6-5 



i6-5 



i6-5 



i8-5 



i8-o 



17-5 





820 



9 



22-S 



i8-o 



185 



i8-5 



i8-5 



20-5 



19-5 



19-0 





818 



7 



26-0 



2I"0 



21-5 



22'0 



21-5 



24*0 



21-5 



22-0 





808 



5 



330 



260 



26-5 



27-5 



26s 



30'o 



25-5 



27-0 





788 



3 



51-0 



39-0 



40-5 



42-5 



40-5 



47-0 



38-5 



42-5 



•765 



