158 Transactions.—M iseellaneous. 
Good brickwork in cement ... iis 550 
Best brickwork in cement... 930 
Neat Portland cement, 9 months old 5970 
1 of cement to 3 of sand = 2400 
1 of cement to 5 of sand ss 1700 
Betou agglomeré, 15 months old, tT 
hydraulic lime of Argentine 
Same, 18 to 31 months old ... 8300 to 5360 
2650 
Betou agglomeré, 21 to 30 months old, "| 5650 to 7180 
with hydraulic lime of Theil 
Betou agglomeré, 2 months old, aie 
from 1 of hydraulic lime and u} 1690 
cement to 5 of sand 
Same, with 1 part of cement only ... 1860 
Same, with 4 part of cement only ... 1450 
Chalk ... iss ‘ie oe ets 830 
Ordinary sandstones ... se is 8300 to 4400 
Compact sandstones ... en = 9800 
Limestones SiS = wa 8100 to 8500 
Caen stone... aa ae 1100 
Basalts and granites ... . 9500 to 13,000 
Smooth dressed ashlar, in large hicks ‘with cement mortar, is practi- 
eally as strong as the stone of which it is built, but rubble masonry is 
three-fifths weaker. We may, therefore, assume the crushing strength of 
this class of work, built from our native bluestones and hard breccias, at 
4000 lbs. per square inch. 
From the above data the relative thickness of walls of equal strength in 
the ordinary building materials would be — as follows :— 
1.00 
Good brickwork . 
Ordinary eee: ei os — se 0.33 
Bluestone rubble ee vac ae -_ 0.15 
Betou agglomeré : na 0.10 
Although, in theory correct, a is pcanuieally impossible to adopt this 
standard, for we all know that nine inch brick walls are sufficient for a one 
storey house; but the idea of reducing them to one inch is altogether too 
absurd to be entertained, no matter how strong the material may be. The 
objection, also, holds good with the thickest walls; for weight and breadth 
of bearing are as much required as cohesive strength. Those who maintain 
that concrete is superior to every other building material advocate thin 
walls, or at least, affirm that they are permissable, and many houses have 
been erected, the sides of which resemble monumental slabs more than 
