770 
PROCEEDINGS OE SECTION II. 
First, where the subsoil is known to be uneven, and consequently 
tbe filling of unequal depth, piles are driven until the solid ground is 
reached. After they have all been driven, the heads are cut off below 
high-water mark. Beams are then laid on them of sufficient width to 
take in the whole thickness of the walls of the superstructure. These 
beams are piped down on the piles with iron straps and bolts, and 
the beams themselves are bolted and strapped together at the angles, 
and held together immediately with bolts at short intervals. 
The second system, which is termed a floating foundation , is of 
course used Avhen the subsoil is known to be comparatively level and 
the filling of nearly equal depth. The ground is first cleared down to 
about two feet below high-water marl*. A double layer of thick 
planking is then laid in reverse angles to each other, and on this 
planking beams are laid broad enough to embrace the full thick- 
ness of the walls. The planking and beams are then firmly bolted 
together. This system is, I think, what Professor Milne has named 
f ree fo u n da Hons. 
In the upper parts of the city there is no difficulty in getting 
good floors to build upon. Sound clay beds extend over a larg3 area, 
and, where the sandhills have been levelled, there are good sandbeds 
which make admirable floors to build upon if kept from spreading. 
Wherever the buildings, and on whatever material they rest, it is at 
the foundations they must be held together. 
In seeking to accomplish, this, there were some who preferred the 
floating foundations to piles on the made ground. Mistakes were 
liable to occur through carelessness or miscalculation — one part of the 
foundation settling more under the load than another, cracks and 
rents being the result. In spite of these considerations there were 
many buildings erected on foundations constructed on this principle 
that stood the test of time. In contradistinction to this it was urged 
that in a pile foundation there are none of these difficulties if the 
piles are driven down to absolute stoppage, so that the settlement 
under the weight of the structure is wholly impossible ; but then the 
centre of motion instead of being at the sill of the buildings is at the 
foot of the piles, and the blow from the motion of the earthquake is i 
communicated direct to the building, and therefore affecis it more < 
severely than a building on a floating foundation. The made ground; 
under the building, acting as a cushion, deadens the blow. 
There are several systems of construction practised for the' 
superstructure. One is to erect a wooden frame strong enough to < 
support the floors and roof; the exterior being built of souud brick 
masonry, having hoop-iron well tarred laid in longitudinally for every 
30 or 36 inches in height, heavy bond-iron girtiug the building at. 
floors and roof to support the timbers, iron anchors from the outside' 
of walls firmly fastened to the flooring joists, ceiling joists, andJ 
rafters to bind the brickwork to the frame. A more expensive plan* 
is to girt the building at the foundations, floor, and roof witlu 
bond iron, having vertical rods at pillars and angles ; these were 
supplemented with angle rods bolted to them where practicable, the j 
walls being built of brick to satisfy the underwriters. It wae- [ 
calculated that a building erected on this principle, and being m 
arrangement of triangles, would have strains of extension that would! 
