R. H. Richards—Jet Aspirator for Laboratories. 425 
Another experiment to determine the amount of time needed 
to exhaust a vessel of known capacity. Aspirator a? :w?=5:1. 
Tr pre Water pres. 
approximately. H—h. Time. lapproximately. H—A. Time. 
725 $4min.* | 2774 676 4 min. 
437 Cc iz 403 5 “ 
“ 739 13 oon “ "12 54 “ 
6 739 2 c“ 6% “c 725 64 66 
“ 497 / 
6s 0 0 “cc t “c 799 gs 
- 255 $ be ae 734 Lo: ¢ 
s 460 1 A ss 737 is: * 
= 549 :.. * bi 739 iz.* 
. 633 3 fe sts 739 TT dl 
In order to ascertain how long any vessel will require for 
exhaustion the law is directly as the volume. A flask of dou- 
ble capacity takes twice as long. 
e experiments below were made to ascertain the maximum 
exhaustion attainable by these four aspirators, the readings 
being taken much more closely than those given previously. 
Barometer 767-2™™, air 764° F. 
Aspirator. Water temp. G, G,. H. h. H—A 
No. 1 44° 1740 520 744 0 744 
No. 2 734 1740 520 744 0 744 
No. 3 74 1740 500 744 0 744 
0. 4 73 1740 500 743 1} 7414 
Table showing the amount of rarefaction attained by each 
oo gas when doing its best work by means of the pressure at 
an 
Tape VI. 
Aspi- H—A. Aq. vapor Water Water Bar. B+(H-A+V). 
Faor. — temperature. pressure. B. 
No.4 7414 ~— 2109 73 2644 767-2 4°61 
No.5 738k ~— 2109 73 2378 764° 1 
No.6 = 734 20°47 72 2774 7 8°5 
No.7 145 20°47 72 2301 764" 5 68°53 
The column B—(H—A+V) in this table shows us the error of 
the aspirator, i.e. the number of millimeters that its air exhaus- 
tion varies from the theoretical perfection to be aimed at. The 
pump will never be able to eliminate the tension of aqueous 
* Aspirator attached to manometer only ; cock Cs, fig. 14, was closed. 
a dine other figures record a series with C, open and the aspirator attached to 
flask without any water in it, of 1340 c.c. capacity. 
