aaa Searcy ee er ce ee te ee eee ee ee ere ee ee eee ee ener hee 8 EES ES 
the South and Middle Yuba, California. 17 
Besides the main reservoir se a smaller lakes or reser- 
voirs, of which the principal one is Lake Fauchaeig® on the 
course of Cajion Creek, perhaps font eaniles below the main res- 
poy ir. A timber dam of thirty feet in height has been con- 
tructed across its outlet, forming = reservoir of about two 
indeed acres, giving a volume of 217,0 0, of cubic feet. 
Dams have also been erected across oa ie outlets of several small 
lakes to the west and south of Lake panera from the outlet 
of one of which the main canal commen 
The Eureka Hr is constructed sarily, jin eee: and partly 
as a wooden flum _ The dim ensions of the main fats are 
feet per mile. The disc sais is ninety-six and f fectinta niles 
dredths cubic feet per second, or 3,485 miners’ inches, taking 
> depth of water at two feet nine inches. If the full depth 
and thirteen and thirty -three-hundredths cubic feet, or 4,306 
inches ; but on account of the irregularity in the grade and. the 
subsidences which have taken place, it is not practicable, at pres- 
ent, to fill it to its full capacity. 
Taking 3,485 inches as the supply, and deducting ten per cent 
for loss by leakage, evaporation, etc., will leave 3, _ oe pa the 
supply which can be made availa able. The practical result 
which is 3000 inches, agrees very closely with this ; 3 037 inches 
of a constant discharge during a working day o ten hours is 
ual to 7,289 inches for twenty-four hours, heb latter quan- 
tity, therefore, is the available capacity of the canal, irrespec- 
tive of the Miners ’ and other confluent ditches. The disch 
feet, equals eight and one-third millions of cubic feet for twenty- 
four hours e yearly complement is therefore 3,041,000,000 
cubic feet. 
The storage capacity for the supply of the Canal is thus stated : 
Cafion Creek pale shies ES eee 933 millions cubic feet. 
Reed PAUCHSTIA .» os 05) owen sot thees* nie ft Siow 
Smaller lak —" oc kee b ais ts oa bene ts 100. * ati Fore 
1 9 50 “ a “ 
the a’ yt ade sled or the last fifteen years has been 18°64. In the mountains, rain 
rarely after the month of September. It is then converted into snow Bx 
the co of the clim it commences few 
following months all t and rivers have a plentiful supply of water. 
The rain-fall of the mountains (or the a which falls 
water) is from fifty to seventy per cent more than the rain-fall of the valleys; 
(according to experiments which I sie on the Middle Yuba in 1856-7, I found 
that seven feet of snow measured, after its Ang Pigdetat water; the refore, 96 a 
approximation, the fall of snow, divided by seven, is equal to the rain-fall.) 
Am. Jour. Sci.—Szconp Szrizs, VoL. xt iti 118—JuLy, 1865. dehes 
