« 
58 Mr. T. Tate’s Experimental Researches on the 
AB awide glass tube, containing the liquid, 
about 2 feet.in length, graduated into units 
of cubic inches, or into units of half cubic 
inches, as the case may be; © and D two 
equal plates of polished slate having equal 
orifices bored through their centres; the 
plate C is cemented (with a resmous cement) 
to the bottom of the tube, and the filter e 
is cemented to both plates, so that all lateral 
discharge from the filter is stopped, and at 
the same time the filter presents a surface, in 
contact with the liquid, equal to the section 
of the orifices of the plates. All liquids, 
before being used in the filtrometer, were 
twice filtered through ordinary filtering 
paper, and the top of the filter tube AB was 
covered during the experiment to prevent any 
dust from falling intothe hquid. The tube 
AB was filled up, with the liquid, to a cer- 
tain point of the graduation, and then the 
time at which the liquid, in its descent, ar- 
rived at the different points of the gradua- 
tion was duly noted. 
Heperiment XVI. 
The filter used in this experiment was common wood-charcoal 
half an inch in thickness. The liquid was distilled water. The 
diameter of the orifice of the plate was ;4ths of an inch. The 
filter-tube was graduated into 8 units, each contaming half 
a cubic inch, and the 8 divisions measured 9:2 inches. The 
temperature was 56° throughout the experiment. The results 
recorded in the third column of the following Table are obtained 
by dividing the unit of space by the mean of the times taken in 
describing the two consecutive units of space; thus the velocity 
epee 46+55 1 
at 4= 1 + ————_ = —.. 
2 50 
| | 
i : Val f 
Hig of loony tine| Gomer | EEE, | vaso 
liquid, “Dp > descent, ee Ah ; by formula 
h, 7 | v. ~ 203 (4). 
vied aa ee — 
| 8 0 | fe 0 
7 27 Z5 25 26°5 
‘ - ae s 57°5 
5 94 at a5 | 94-0 
‘ oe 35 2s 139-0 
3 195 Se oe 196°0 
2 272 | xt a 277-0 
1 | 400 | 415-0 
