[32] 31 
is every wliere at liand, to puddle the bed of tlic canal, if necessary. 
Supposing therefore, that its losses fi-om titrations and evaporation, 
equalled in one month tlje cube of its prism, or 519,200 cubic yards, 
this would certainly be their maximum, whilst the evaluation of 
492,034 cubic yards of water, which we have given, as the supply 
from the reservoir of Deep Creek, in one month, is its minimum. 
For, it must be remembered, that we valued this supply from the low- 
est result, obtained at the lowest stage of Deep Creek, when it gave 
only 5^ cubic feet in a second. . 
We have allowed no loss for the evaporation for the surface of the 
reservoir, as it will be compensated by the frequent rains which fall 
on the summit of the Alleghany. From observations made in July, 
August, September, and October, 1824, in the Valley of Deep Creek, 
w^e have ascertained that there fell. 
From 19th to oOtb July, 4 days of rain, 4.36 inch. 55^ mean temperature. 
'* 1 to 31 Auj^ust, 8 days of rain, 2.31 " 63° " 
" 1 to 31 Sept. 12 days of raii», 3.15 " 51° " 
" 1 tool Oct. 9 days of rain, 3.19 " 44 » 
Trom 19th July to 31st Oct. 23 days of rain. 13 " 10 
During 104 days, of which 33 were rainy, there fell 13.01 inches 
of rain. The evaporation was 0.10 Indies a day, and during the 
104 days, 10.40 inches; of course the rain more than supplied the 
loss of evaporation. 
The temperatni-es marked above, are the mean temperatures of 
the rainy days. The highest temperatures in that Valley, during 
these months, were at midday, in July, 76° — in August, 74° — in 
Se])temher, 70° — in October, 72°. Tlie lowest were at 6 in the 
morning; in July, 53° — in August, 44° — in September, 32*, and in 
October 25*. 
From these observations, it is evident, tliat less evaporation is to be 
apjjrehended in the Valley of Dee]) Creek, than in regions more to 
the level of the Ocean: besides, by raising the dam which forms its 
reservoir, we might add to it a «|uantity of water, sufKcicnt to supply 
all the loss of its evapoi-ation and filtration. We will conclude these 
remarks on the reservoir of Deep Creek, by observing, that its sur- 
face lies below the mouths of its tributaries; and that they might, 
tlierefare, at small expense, be turned into reservoirs, to preserve the 
waters of the Valley, when (tiie great reservoir of Deep Creek be- 
ing full,) they w ould otherwise esca^rc over the dam. For tliis pur- 
pose, the dams of these small streams should have sluice gates, to dis- 
tibute their supplies, whenever required. 
Summit Lcrel of the Middle Section. 
From tliese observations it is evident, that the eastern and western 
branches of the middle section possess sufficient supplies to repair 
their lor>ses from nitrations and evaporation. T!ie nr.st is 15 and the 
second 143 miles in length, and botli 29J miles. If we subtract this 
length fVom that of tJie whole Deep Creek route, 41 miles 718 yards, 
