Laws of Absorption of Liquids by Porous Substances. 119 
Depth of the Corresp. time | value of T by 
column of liquid,| in seconds, formula (9) 
T, . 
h. 
6 0 0 
5 33 32°6 
4 68 68:0 
3 108 108-2 
2 173 1790 
1 218 218-0 
0 378 368°0 
The formula expressing the relation between T and A is 
T= 868 150M a SS 89) 
Hence we find 
1 
h2 
v= 75 > OR aS Seta eae (10) 
that is to say, for orifices of this diameter, the velocity of discharge 
varies directly as the square root of the depth of the column of 
liquid. 
In general it has been found that 
Weal. ccc ie srdewe yh whieh nia eh Ws weed 
By integrating the equation v= ee 
7p We find 
T=a—yh'-, & e e ° e ® e (12) ! 
1S tial | 
where y= aoe 
In formule (9) and (10), n=4, e=74, and y=150. When 
n=1, we find from equation (11), 
Peay los hy te iore: «vis! eoeey G19) 
2°30218 
aoe 
This formula represents the law of descent of the liquid in the 
following experiment. 
Experiment XXVIII. 
In this experiment the diameter of the orifice was ~4 5th of 
an inch nearly. 
where y= 
Depth of the | Corresp. time | value of T by 
column ofliquid,} in minutes, formula (14). 
h. T. 
