Rafael Guastavino

a new additional strength

takes bond with it, and also with the course laid on top. As soon as the cement sets, we will have shearing resistance represented by 17,820 pounds per square foot

[M]ortar laid over the first course

[I]f we put another course over the first

A "Timbrel Vault" of a single thickness of brick or (Fig. 10) has no more resistance than an arch or vault built on the " Gravity System"; because, no matter how good the mortar.., there is only one vertical joint, and the bricks or tiles …

Italy and Spain at this epoch had no text-books of their own; all were translations from the French and English works.

[A]ll conscientious professors were inclined to give coefficients of resistance only for the gravity system, and all their books and teachings were on the gravity system, except for tensions of materials working in that way.

Could the professors and scientific men of these countries have seriously taken into consideration... cohesive strength.., though they knew of the existence of some cements.

the English, French and Germans... [O]n account of the erroneous form of their bricks, and the poor method of using their materials.., when the walls... were torn down and the bricks taken out, they were so nearly clean, without any mortar …

Nothing had then been written in regard to cohesive construction as applied to the "timbrel arch... due to the following

text-books in general did not refer to any save the gravity system. These doctrines or ideas prevail yet, and are now the basis of our teachings.

The basis of these materials is mortar that does not require exposure to the air for its transformation or setting quality—that is, and ; but for our specialty we must have cements of the quality of Portland.

The use of the "Cohesive System" was rendered impossible to many nations because they had neither the material, nor the knowledge of its use... while... all civilizations... could make use of the gravity system.

"Cohesive Construction"... materials must... have proper physical conditions... but it is absolutely necessary that the chemical properties of the substances... be taken into consideration.

[M]aterials... in construction by gravity only require... .

[T]hough man cannot again use the parts of "Cohesive Construction" for modern buildings, their ruins inspire respect and ; and only Nature, with her slow... disintegration, can take from this... material for her immense and eternal …

The structures built by the "Gravity System" can at any time be taken down in the pieces... Thus, the stone or brick... of a temple or monument... can to-morrow belong to or form... [another structure]...

In "Cohesive Construction"... the components cannot be separated without destroying the integral mass. To these belong the Babylonian walls of brick with hydraulic mortar; the vaults and cupolas of the Assyrian, Persian, Arabian, Roman and …

[T]he... mechanical, system is... where all the pieces can be separated one by one and then rebuilt in the same or similar manner. To this class belong the pyramids of Egypt and the Greek temples, etc.

The second has for a basis the properties of cohesion and assimilation of several materials; which, by a transformation more or less rapid, resemble Nature's work in making conglomerates.

The first is founded in the resistance of any solid to the action of gravity when opposed by another solid. From these conjuctive forces, more or less opposed to one another, results the equilibrium of the total mass, without taking into …

We... divide construction... into two classes: ...First, "Mechanical Construction," or, construction by gravity. Second, "Cohesive Construction," or, construction by assimilation.

not without the valuable assistance and confidence of the eminent architects

On account of these special advantages... this experimental work culminated in the United States.., in New York and Boston, with specimens that have no rivals in any part of the world for lightness and resistance.