228 The Primary Upheaval of the 
causing the thread attached to the ball to form with the ver- 
tical an angle of from twenty to thirty degrees. 
Denoting by @ the coefficient corresponding to that ball, 
and by ® the observed angle, the surface velocity was found 
by the ordinary formula X = 6 V 8. 
I have known cases where engineers, with a mere know- 
ledge of the fall per mile in a river, and the sectional area, 
taken at one point only, have, from such very insufficient 
data, endeavoured to compute the discharge. For the usual 
formula, by Eytelwein, from which have been derived the 
tabulated quantities in Beardmore’s Hydraulic Tables, and 
other works, is only applicable under the following condi- 
tions, which never occur unless in carefully constructed arti- 
ficial channels: viz. 
Unchanging sectional area. 
Unchanging wetted perimeter. 
If on the length corresponding to the fall, a great number 
of cross sections had been taken, so as to admit of a mean 
sectional area, and mean perimeter of the water contour being 
deduced therefrom, then of course a rough approximation to 
the discharge could have been computed. 
Many instances might be cited of disappointment attendant 
on the completion of hydraulic works, owing to the prelimi- 
nary calculations having been made on erroneous principles. 
For instance, when the works for conducting water into 
Edinburgh were completed, the quantity of water delivered 
was only one-sixth of the:quantity estimated by the designer 
of the work, although he himself acknowledged that the 
work had been executed in strict accordance with his plans. 
ArT. XIX.—On the Primary Upheaval of the Land round 
Melbourne, and the recent Origin of the Gypsum or Sul- 
phate of Lime in the great swamp between Batman's and 
Emerald Hills, Flemington, Williamstown, and Melbourne, 
illustrated by a large number of Specimens from that Locality. 
By WitL1AmM Buanpowsk1, Esq. 
THE land which now constitutes the colony of Victoria 
owes its origin to the same mighty convulsion which upheaved 
the Australian Alps. Beginning where those mountains cross 
the latitude of 37°, eruption followed eruption in rapid suc- 
cession, the plutonic agency constantly advancing westward, 
