318 К T'ransactions.— Geology. 
source, yet this principle prevails that the curves gradually approximate, 
showing that had the source been accepted at a lower point than Mount Nix, 
the law would have been vindicated. 
For the ealeulation of the ordinates of an ellipse for the valley of the 
Molyneux, we have: the length equal to 944,040 feet, rise 9,101 feet. 
By ELLIPSE. By Survey. DIFFERENCES, 
At source 0000 av 3 0000 mis 000 
5050 8127 3077 
7405 8477 1072 
š А à 8084 8601 5H 
At intermediate points 8670 8890 990 ` 
8781 8929 148 
L 8886 i4 8951 D 65 
At exit to sea "T 9101 9101 00 
The next valley that the maps of the Survey Department enabled me to 
examine was that of the Cardrona, a rapid mountainous torrent flowing into 
the Molyneux near to its issue from Lake Wanaka, The length of the valley 
is about 31 miles, and the rise, from the Molyneux to the Crown Mountains, 
4,799 feet. This example, considering the features of the mountain district, 
shows a tolerably near approximation to the ellipse, as given below :— 
By ELLIPSE, By Survey, DIFFERENCES. 
At source... 0000 sa 0000 000 
auc RAM MS BN ie No 
Atexit ^ .. © 4199 oe 4799 s 000 
The last example with which I will trouble you is that of the Mataura, 
with its east and west bends, a painting of whose scenery is on the table, taken 
on its first exploration, in J anuary, 1857. The east branch being the shorter 
is not properly the main river ; it will thus be seen that its curve is not so 
remarks applicable as have been made in regard to the Molyneux. The 
comparison of the east branch gives the following results :— 
By ELLIPSE, By Survey, DIFFERENCES, 
At source du Mus 0000 а. 0000 
3201 i 4547 1346 
wes ae 4773 tk 557* 
s ' à TNR 4905 
At intermediate points 4p ы “ш r 
5110 : 5129 
5173 5160 13 
At exit to sea vite ROM о BOOK 
and the west branch, as follows :— 
