like the ten fingers and ten toes.'

These are the certainties of the engineer; so far he
finds a solid footing and clear views. But the province of

formulas and constants is restricted. Even the mechanical
engineer comes at last to an end of his figures, and must

stand up, a practical man, face to face with the discrepancies
of nature and the hiatuses of theory. After the machine is

finished, and the steam turned on, the next is to drive it;
and experience and an exquisitesympathy must teach him where

a weight should be applied or a nut loosened. With the civil
engineer, more properly so called (if anything can be proper

with this awkward coinage), the obligation starts with the
beginning. He is always the practical man. The rains, the

winds and the waves, the complexity and the fitfulness of
nature, are always before him. He has to deal with the

unpredictable, with those forces (in Smeaton's phrase) that
`are subject to no calculation'; and still he must predict,

still calculate them, at his peril. His work is not yet in
being, and he must foresee its influence: how it shall deflect

the tide, exaggerate the waves, dam back the rain-water, or
attract the thunderbolt. He visits a piece of sea-board; and

from the inclination and soil of the beach, from the weeds and
shell-fish, from the configuration of the coast and the depth

of soundings outside, he must deduce what magnitude of waves
is to be looked for. He visits a river, its summer water

babbling on shallows; and he must not only read, in a thousand
indications, the measure of winter freshets, but be able to

predict the violence of occasional great floods. Nay, and
more; he must not only consider that which is, but that which

may be. Thus I find my grandfatherwriting, in a report on
the North Esk Bridge: `A less waterway might have sufficed,

but the VALLEYS MAY COME TO BE MELIORATED BY DRAINAGE.' One
field drained after another through all that confluence of

vales, and we come to a time when they shall precipitate by so
much a more copious and transient flood, as the gush of the

flowing drain-pipe is superior to the leakage of a peat.
It is plain there is here but a restricted use for

formulas. In this sort of practice, the engineer has need of
some transcendental sense. Smeaton, the pioneer, bade him

obey his `feelings'; my father, that `power of estimating
obscure forces which supplies a coefficient of its own to

every rule.' The rules must be everywhere indeed; but they
must everywhere be modified by this transcendental

coefficient, everywhere bent to the impression of the trained
eye and the FEELINGS of the engineer. A sentiment of physical

laws and of the scale of nature, which shall have been strong
in the beginning and progressively fortified by observation,

must be his guide in the last recourse. I had the most
opportunity to observe my father. He would pass hours on the

beach, brooding over the waves, counting them, noting their
least deflection, noting when they broke. On Tweedside, or by

Lyne or Manor, we have spent together whole afternoons; to me,
at the time, extremely" target="_blank" title="ad.极端地；非常地">extremely wearisome; to him, as I am now sorry to

think, bitterly mortifying. The river was to me a pretty and
various spectacle; I could not see - I could not be made to

see - it otherwise. To my father it was a chequer-board of
lively forces, which he traced from pool to shallow with

minute appreciation and enduring interest. 'That bank was
being under-cut,' he might say. `Why? Suppose you were to

put a groin out here, would not the FILUM FLUMINIS be cast
abruptly off across the channel? and where would it impinge

upon the other shore? and what would be the result? Or
suppose you were to blast that boulder, what would happen?

Follow it - use the eyes God has given you - can you not see
that a great deal of land would be reclaimed upon this side?'

It was to me like school in holidays; but to him, until I had
worn him out with my invincible triviality, a delight. Thus

he pored over the engineer's voluminous handy-book of nature;
thus must, too, have pored my grand-father and uncles.

But it is of the essence of this knowledge, or this knack
of mind, to be largely incommunicable. `It cannot be imparted

to another,' says my father. The verbal casting-net is thrown
in vain over these evanescent, inferential relations. Hence

the insignificance of much engineeringliterature. So far as
the science can be reduced to formulas or diagrams, the book

is to the point; so far as the art depends on intimate study
of the ways of nature, the author's words will too often be

found vapid. This fact - that engineering looks one way, and
literature another - was what my grand-father overlooked. All

his life long, his pen was in his hand, piling up a treasury
of knowledge, preparing himself against all possible

contingencies. Scarce anything fell under his notice but he
perceived in it some relation to his work, and chronicled it

in the pages of his journal in his always lucid, but sometimes
inexact and wordy, style. The Travelling Diary (so he called

it) was kept in fascicles of ruled paper, which were at last
bound up, rudely indexed, and put by for future reference.

Such volumes as have reached me contain a surprising medley:
the whole details of his employment in the Northern Lights and

his general practice; the whole biography of an enthusiastic
engineer. Much of it is useful and curious; much merely

otiose; and much can only be described as an attempt to impart
that which cannot be imparted in words. Of such are his

repeated and heroic descriptions of reefs; monuments of
misdirected literaryenergy, which leave upon the mind of the

reader no effect but that of a multiplicity of words and the
suggested vignette of a lusty old gentleman scrambling among

tangle. It is to be remembered that he came to engineering
while yet it was in the egg and without a library, and that he

saw the bounds of that profession widen daily. He saw iron
ships, steamers, and the locomotive engine, introduced. He

lived to travel from Glasgow to Edinburgh in the inside of a
forenoon, and to remember that he himself had `often been

twelve hours upon the journey, and his grand-father (Lillie)
two days'! The profession was still but in its second

generation, and had already broken down the barriers of time
and space. Who should set a limit to its future

encroachments? And hence, with a kind of sanguine pedantry,
he pursued his design of `keeping up with the day' and posting

himself and his family on every mortal subject. Of this
unpractical idealism we shall meet with many instances; there

was not a trade, and scarce an accomplishment, but he thought
it should form part of the outfit of an engineer; and not

content with keeping an encyclopaedic diary himself, he would
fain have set all his sons to work continuing and extending

it. They were more happily inspired. My father's engineering
pocket-book was not a bulky volume; with its store of pregnant

notes and vital formulas, it served him through life, and was
not yet filled when he came to die. As for Robert Stevenson

and the Travelling Diary, I should be ungrateful to complain,
for it has supplied me with many lively traits for this and

subsequent chapters; but I must still remember much of the
period of my study there as a sojourn in the Valley of the

Shadow.
The duty of the engineer is twofold - to design the work,

and to see the work done. We have seen already something of
the vociferous thoroughness of the man, upon the cleaning of

lamps and the polishing of reflectors. In building, in road-
making, in the construction of bridges, in every detail and

byway of his employments, he pursued the same ideal.
Perfection (with a capital P and violently under-scored) was

his design. A crack for a penknife, the waste of `six-and-
thirty shillings,' `the loss of a day or a tide,' in each of