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THE inventions that have been thus far
described fall into two classes--first, those
that were fundamental in the great arts and
industries which have been founded and
established upon them, and, second, those that
have entered into and enlarged other arts that
were previously in existence. On coming to
consider the subject now under discussion,
however, we find ourselves, at this writing,
on the threshold of an entirely new and
undeveloped art of such boundless possibilities
that its ultimate extent can only be a matter of
conjecture.
Edison's concrete house, however, involves
two main considerations, first of which was the
conception or creation of the IDEA--vast
and comprehensive--of providing imperishable
and sanitary homes for the wage-earner by
molding an entire house in one piece in a single
operation, so to speak, and so simply that
extensive groups of such dwellings could be
constructed rapidly and at very reasonable cost.
With this idea suggested, one might suppose
that it would be a simple matter to make molds
and pour in a concrete mixture. Not so,
however. And here the second consideration
presents itself. An ordinary cement mixture is
composed of crushed stone, sand, cement, and
water. If such a mixture be poured into deep
molds the heavy stone and sand settle to the
bottom. Should the mixture be poured into a
horizontal mold, like the floor of a house, the
stone and sand settle, forming an ununiform
mass. It was at this point that invention
commenced, in order to produce a concrete
mixture which would overcome this crucial
difficulty. Edison, with characteristic
thoroughness, took up a line of investigation,
and after a prolonged series of experiments
succeeded in inventing a mixture that upon
hardening re- mained uniform throughout its
mass. In the beginning of his experimentation
he had made the conditions of test very severe by
the construction of forms similar to that shown
in the sketch below.
This consisted of a hollow wooden form of the
dimensions indicated. The mixture was to be
poured into the hopper until the entire form was
filled, such mixture flowing down and along the
horizontal legs and up the vertical members. It
was to be left until the mixture was hard, and
the requirement of the test was that there should
be absolute uniformity of mixture and mass
throughout. This was finally accomplished, and
further invention then proceeded along
engineering lines looking toward the devising of
a system of molds with which practicable
dwellings might be cast.
Edison's boldness and breadth of conception are
well illustrated in his idea of a poured house,
in which he displays his accustomed tendency to
reverse accepted methods. In fact, it is this
very reversal of usual procedure that renders it
difficult for the average mind to instantly grasp
the full significance of the principles involved
and the results attained.
Up to this time we have been accustomed to see
the erection of a house begun at the foundation
and built up slowly, piece by piece, of solid
materials: first the outer frame, then the
floors and inner walls, followed by the
stairways, and so on up to the putting on of the
roof. Hence, it requires a complete
rearrangement of mental conceptions to appreciate
Edison's proposal to build a house FROM
THE TOP DOWNWARD, in a few hours,
with a freely flowing material poured into
molds, and in a few days to take away the molds
and find a complete indestructible sanitary
house, including foundation, frame, floors,
walls, stairways, chimneys, sanitary
arrangements, and roof, with artistic
ornamentation inside and out, all in one solid
piece, as if it were graven or bored out of a
rock.
To bring about the accomplishment of a project
so extraordinarily broad involves engineering and
mechanical conceptions of a high order, and, as
we have seen, these have been brought to bear on
the subject by Edison, together with an
intimate knowledge of compounded materials.
The main features of this invention are easily
comprehensible with the aid of the following
diagrammatic sectional sketch:
It should be first understood that the above
sketch is in broad outline, without
elaboration, merely to illustrate the working
principle; and while the upright structure on
the right is intended to represent a set of molds
in position to form a three-story house, with
cellar, no regular details of such a building
(such as windows, doors, stairways, etc.)
are here shown, as they would only tend to
complicate an explanation.
It will be noted that there are really two sets
of molds, an inside and an outside set, leaving
a space between them throughout. Although not
shown in the sketch, there is in practice a
number of bolts passing through these two sets of
molds at various places to hold them together in
their relative positions. In the open space
between the molds there are placed steel rods for
the purpose of reinforcement; while all through
the entire structure provision is made for water
and steam pipes, gas-pipes and electric-light
wires being placed in appropriate positions as
the molds are assembled.
At the centre of the roof there will be noted a
funnel- shaped opening. Into this there is
delivered by the endless chain of buckets shown
on the left a continuous stream of a special
free-flowing concrete mixture. This mixture
descends by gravity, and gradually fills the
entire space between the two sets of molds. The
delivery of the material--or "pouring," as
it is called--is continued until every part of
the space is filled and the mixture is even with
the tip of the roof, thus completing the
pouring, or casting, of the house. In a few
days afterward the concrete will have hardened
sufficiently to allow the molds to be taken away
leaving an entire house, from cellar floor to
the peak of the roof, complete in all its
parts, even to mantels and picture molding, and
requiring only windows and doors, plumbing,
heating, and lighting fixtures to make it ready
for habitation.
In the above sketch the concrete mixers, A,
B, are driven by the electric motor, C. As
the material is mixed it descends into the tank,
D, and flows through a trough into a lower
tank, E, in which it is constantly stirred,
and from which it is taken by the endless chain
of buckets and dumped into the funnel-shaped
opening at the top of the molds, as above
described.
The molds are made of cast-iron in sections of
such size and weight as will be most convenient
for handling, mostly in pieces not exceeding two
by four feet in rectangular dimensions. The
subjoined sketch shows an exterior view of
several of these molds as they appear when bolted
together, the intersecting central portions
representing ribs, which are included as part of
the casting for purposes of strength and
rigidity.
The molds represented above are those for
straight work, such as walls and floors. Those
intended for stairways, eaves, cornices,
windows, doorways, etc., are much more
complicated in design, although the same general
principles are employed in their construction.
While the philosophy of pouring or casting a
complete house in its entirety is apparently
quite simple, the development of the engineering
and mechanical questions involves the solution of
a vast number of most intricate and complicated
problems covering not only the building as a
whole, but its numerous parts, down to the
minutest detail. Safety, convenience,
duration, and the practical impossibility of
altering a one-piece solid dwelling are
questions that must be met before its
construction, and therefore Edison has
proceeded calmly on his way toward the goal he
has ever had clearly in mind, with utter
indifference to the criticisms and jeers of those
who, as "experts," have professed positive
knowledge of the impossibility of his carrying
out this daring scheme.
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