of Capillary Action. 255 
by a liquid filling small orifices or perforations made in rigid 
plates of different thicknesses. 
Let AC represent a wide glass tube, closed at Fig. 1. 
the top, and having a perforated plate He, capable 
of being wetted, cemented to its lower extremity ; 
1B a glass tube, about half an inch in diameter, 
cemented to this plate, open at its lower extremity, 
and communicating with the tube AC; e asmall 
perforation made in the plate; DB a glass vessel 
containing water or any other liquid to be ex- 
amined. ‘The tube EB is graduated from the 
exterior surface of the plate into inches and 
decimal parts of an inch. ‘The tubes being filled 
with water, and the extremity B inserted in the 
water contained in the vessel DB, it will be 
found that the orifice e may be raised for some 
inches above the level FD of the water in the 
vessel before the atmospheric air will enter the 
orifice. The height C D, at which the external 
air enters the orifice, obviously gives us the measure of the ca- 
pillary resistance of the liquid in the orifice. The followmg 
results of experiments show that, the temperature being constant, 
the height of the column C D, measuring the capillary resistance 
of the liquid, varies inversely as the diameter of the orifice. 
The experiments recorded in the following Table of results, 
were made with the apparatus represented in fig. 1. The orifices 
were made in plates of gutta percha by means of fine steel wires, 
whose diameters had been previously determined, Slight oscil- 
lations and other extraneous causes having been found to affect 
the results of the experiments, each result here given is the mean 
of five experiments. 
Table of results of experiments giving the columns of capillary 
resistance corresponding to different diameters of the orifices. 
The liquid was water at the temperature of 56° F., and the 
thickness of the plate was 05 of an inch. 
Diameter of the |Corresp. column Value of h 
orifice in parts | C D of capillary} by formula 
of an inch, resist. in inches, ee 
dD. h. ‘=39 D 
es 3°35 3:32 
en 1:80 1-82 
ee 1-40 1:36 
ds 112 l-ld 
