318 W. 
ey > 
B. Rogers on Binocular Vision. 
* 
To give an idea of the expense entailed by the tides of Hang- 
chau Bay, I have cast up the sums disbursed at different ey 
during the reign of Kien-lung, comprising a period of sixty y 
(1736-96) as detailed in the Topography of Hang-chau. 
For the embankment in Hang-chau district :-— 
Taels of es 
Contributed by officers, .......0ss+seeee+ 4,338,0 
Appropriations from Imperial Treasury, 942,800 
Contributed by the people, .....cceceeeues 790,526. 
=e 6,713,390 
e*. 
ai 
ri 
“wee 
ae b 
or about $130,000 per annum, but as silver is now 20 per cent 
earer than it was in that reign, a corresponding reduction should 
perhaps be made from thissum. There is a coast line of about 
180 miles, extending from Chin-hai to Hang-chau which is not 
included in the above; also the shore of the estuary west of Cha- 
poo, has more or less embankment, to the boundaries of Hang- 
chau, which requires large outlays. As the greatest force of the 
tides is experienced on the left, or Hang-chau side of the estuary, 
it is probable that an expenditure of one-third of the above suf- 
ficed to preserve the country from inundation. As the Yellow 
River is “China’s sorrow,” so the “difficulty” of Chih-kiang is 
the Eagre of the T'sien-tang. 
Arr. XXVIIL— Observations on Binocular Vision ; by Professor 
Wii B. Rocers. 
(Continued from p. 220.) 
servations are intended to trace more precisely the development 
of the effect and in connexion with other analogous phenomena 
to furnish suggestions as to the origin in such cases of our pet- 
ception of relie 
We have seen that when we confine the eyes to any particular 
ee Sa: 
ae ee ht ee eee 
stage of convergency, the intersecting lines of the resultant pre- . 
sent themselves in a plane parallel to the paper, but when we al- 
low them within certain limits to vary their convergency, these 
lines assume more or less relief. We have now to add the 1m- 
portant fact that while the lines thus acquire perspectiveness they 
become longer and more acutely inclined to one another. 
