BINNEY'S CASE. 115

the line B C the tail race; and consequently, a natural mill-site,
on the margin of any gradually descending river 0r stream, must
always convey to the mind the idea of a portion of land described
by straight, or curved lines, as from A B C, with a pitch or fall
from B to C, equal to that of A C. The length of the head or
tail race is, comparatively unimportant; it is enough, that they be
practicable; nor is it of any consequence what is the height of the
pitch, or the quantity of water tumbled from B to C; it is suffi-
cient, if it be so high, and so much as to propel the machinery of
a mill. It follows, from this view of the subject, that every such
situation, on the margin of a running stream of water, is a mill-
site, of the kind of those claimed by this plaintiff. And, if water
enough can be brought from A to B, and there is room at B for
building two or more mills; then there may be said to be on that
portion of land just so many natural mill-sites.

One natural mill-site may exist outside of another. Let the
plane of the descending stream, as before described, be followed
up to 1; and then extending the head race thence to the mill po-
sition at 5; and the tail race to the stream at 7; and there will be
represented what may be called, in reference to the stream, and to
each other, an inner and an outer mill-site. Again, one natural
mill-site may exist above another; thus, suppose the head race of
the upper mill to begin at A, that it is stationed at 4, and dis-
charges its water, by a tail race, at 9; and that the lower mill
occupies the ground 8 10 C.

Now these several mill-sites, when owned as the separate pro-
perty of individuals, carry with them certain incidental rights;
each one has a right to the use only of the descending water;
and consequently, he can neither divert, nor consume it; nor use
it to the prejudice of another. And therefore a dam cannot be
raised, A 2, so as to catch and divert the whole stream from 1,
and carry it to the outer mill at 5, and pass it off at 7, leaving
none, or not enough to be taken at A to propel the mill at B. Nor
can the lower mill owner be allowed to raise the water in the
stream, by a dam 8 6, so as to cast it back to 3, and flood the
wheels of the upper mill at 4.

But, a natural mill-site may exist, as any other thing may exist
in nature, without being the separate property of an individual.
Hence, in making out a claim to a natural, unimproved mill-site,
the party must shew, not only, that it exists, but that he is the
owner of it. The whole of the land described by the lines A B C