ve of a culvert to pass the river, of
sixty, eighty, or one hundred feet span and seven hundred feet long.
Twenty trains per day, of thirty cars each, one car holding two yards,
would be twelve hundred yards per day; two million, divided by
twelve hundred, gives 1,666 days.]

[Footnote 3: The most careless observer has doubtless noticed that
the front part of a locomotive rests upon the centre of a track,
having four small wheels; the back and middle part, he will also
remember, is borne upon large spoke wheels,--which are connected
with the machinery; upon the size of these last depend the power and
speed of the engine. The larger the wheels, the less the power, and
the higher the velocity which may be got; again, the wheel remaining
of the same size, by enlarging the dimensions of the cylinders the
power is increased; and the wheels and cylinders remaining the same,
by enlarging the boiler we can make stronger steam and thus increase
the power. There may be seen upon the road from Boston to
Springfield engines with wheels nearly seven feet in diameter, used
for drawing light express-trains; while upon the roads ascending the
Alleghanies may be seen wheels of only three and a half feet diameter,
which are employed in drawing trains up the steep grades. Increase
of steepness of grades acts upon the locomotive in the same manner
as increase of actual load; as upon a level the natural tendency of
the engine is to stand still, while on an incline the tendency is to
roll backwards down-hill.]

* * * * *

HER GRACE, THE DRUMMER'S DAUGHTER.

[Concluded.]

The girl whose suggestion had brought about this change in her
father's household, introducing anxiety and tears and pain where
these were almost strangers, was not exceeding joyous in view of what
she had done. But she was resolved and calm. It was everything to her,
that night when she lay down to rest, to know that the same roof
that covered her was also spread above the prisoner, and all the
joys of youth passed into forgetfulness as she thought and vowed to
herself concerning the future.

It seemed, perhaps, a state of things involving no consequences,
this sympathy that Elizabeth had shared with the gardener Sandy,
when the prisoner's eyes gazed on them from his window, or turned
towards them while he walked in the garden; but Sandy said to himself,
when she told him that they were to have Laval's place in the prison,
"_I