298 Scientific Proceedings, Royal Dublin Society. 
In the following table the irregular variation of the last 
column shows that the law, “flux is proportional to pressure- 
difference,’ is probably the best. 
Temperature Time, 1 
of the _—____________________| Water level = z. logio a 
water. by clock. mins. difference. twa 2 
P.M. 75 11m 151°4 ems. 
10°5° C. 49 682 x 10-3 
5, 8b Om UD 5p 
Now some water was| tipped out. 
P.M. 8h 16m 84:6 ,, 
119 “500 x 
y> 10h 15m 73:8 
Filled | up again. 
A.M. 8b 3m 153-4 ,, 
9° C 37 650 x 
» 88 40m 1A5 Ie 
Some |water poured out} again. 
| acm. 8b 45m 63:3 ,, 
9°5° C. 122 580 x 
,, 10 47m 538 ,, 
195 “470 x 
pM. 1h 32m 45°5 ,, 
176 "5386 x 
95° C. 5 42 28m 35:0 ,, 
251 -481 x 10-8 
, Ba sO 265 ,, 
| mean about 50 x 103 
It is to be noticed that the head of water here bears a far 
greater proportion to the thickness of the wall of peat resisting it 
than would usually be the case in a bog. So that in the actual 
case we shall be still farther removed from Osborne Reynolds’ 
criterion of turbulency ; and therefore the flux will be inversely in 
the viscosity, that is, directly as (1+ -02817)**”, where T is 
the temperature centigrade.’ 
Next to work out the porosity in absolute units, that is, in 
c.c. of water per second passing through 1 sq. em. of a slab when 
the pressure gradient is one dyne per sq. cm. every centimetre 
and the lines of flow are normal to the surfaces. 
1 Poynting and Thomson, ‘‘ Properties of Matter.” 
