rod omitted. If
queen-post trusses are useless, some hundreds of thousands of hog-rods
in freight cars could be dispensed with.

Mr. Goodrich misunderstands the reference to the "only rational and only
efficient design possible." The statement is that a design which would
be adopted, if slabs were suspended on rods, is the only rational and
the only efficient design possible. If the counterfort of a retaining
wall were a bracket on the upper side of a horizontal slab projecting
out from a vertical wall, and all were above ground, the horizontal slab
being heavily loaded, it is doubtful whether any engineer would think of
using any other scheme than diagonal rods running from slab to wall and
anchored into each. This is exactly the condition in this shape of
retaining wall, except that it is underground.

Mr. Goodrich says that the writer's reasoning as to the sixth point is
almost wholly facetious and that concrete is very strong in pure shear.
The joke, however, is on the experimenters who have reported concrete
very strong in shear. They have failed to point out that, in every case
where great strength in shear is manifested, the concrete is confined
laterally or under heavy compression normal to the sheared plane.
Stirrups do not confine concrete in a direction normal to the sheared
plane, and they do not increase the compression. A large number of
stirrups laid in herring-bone fashion would confine the concrete across
diagonal planes, but such a design would be wasteful, and the common
method of spacing the stirrups would not suggest their office in this
capacity.

As to the writer's statements regarding the tests in Bulletin No. 29 of
the University of Illinois being misleading, he quotes from that
bulletin as follows:

"Until the concrete web has failed in diagonal tension and diagonal
cracks have formed there must be little vertical deformation at the
plane of the stirrups, so little that not much stress can have
developed in the stirrups." * * * "It is evident, then, that until
the concrete web fails in diagonal tension little stress is taken
by the stirrups." * * * "It seems evident from the tests that the
stirrups did not take much stress until after the formation of
diagonal cracks." * * * "It seems evident that there is very little
elongation in stirrups until the first diagonal crack forms, and
hence that up to this point the concrete takes practically