BINNEY'S CASE.—2 BLAND. 123

been exacted to the letter, and the party omitting has been held
a trespasser. Keppell v. Bailey, 8 Cond. Chan. Rep. 118.

From which it follows, that, although the works of the company
may be repaired, or anything may be done to render them more
safe, substantial and perfect, yet no additional extent of land can
be taken, nor can any canal, or other work be in any way altered,
remodeled, shifted in its location, or enlarged, so as to be spread
out beyond the extent of this first selected purchase or condemna-
tion.

Now, recollecting what it is, that constitutes a natural mill-site
on the margin of a descending stream; the peculiar character of
this river; and, the general tenor and scope of the Act incorporat-
ing The Potomac Company, we shall find ourselves properly pre-
pared to undertake the consideration of that section of it, which
is in these words :

"And whereas, some of the places through which it may be
necessary to conduct the said canals may be convenient for erect-
ing mills, forges, or other water works, and the persons, posses-
sors of such situation in ay design and improve the same, and it is
the intention of this Act not to interfere with private property, but
for the purpose of improving and perfecting the said navigation,
Be it * enacted, that the water, or any part thereof con-
veyed through any canal or cut made by the said company 130
shall not be used for any purpose but navigation, unless the con-
sent of the proprietors of the land, through which the same shall
be led be first had; and the said president and directors, or a
majority of them, and hereby empowered and directed, if it can be
conveniently done to answer both the purposes of navigation and
water works aforesaid, to enter into reasonable agreements with
the proprietors of such situation concerning the just proportion of
the expenses of making large canals or cuts, capable of carrying
such quantities of water as may be sufficient for the purpose of
navigation, and also for any such water works as aforesaid." 1784,
ch. 35, s. 13.

The great object of this law was the formation of a new line of
navigation; but here a new subject is introduced; mills are pro-
vided for in connection with certain canal portions of that line.
" Some of the pla.ces, it is said, through which it may be necessary
to conduct canals, maybe convenient for erecting mills." Any
place on the margin of this stream, at all convenient for erecting
a mill, must have the qualities which has been described; for,
although it may be said, that this expression may refer to the
middle of the river, or any place through which a canal may be
conducted, of which there may be a great number and variety
along the line of this new navigation; yet, in this case, we are not
allowed to take any such range; because, the claims of this plain-
tiff' are expressly confined to that space of land on the left bank