Architecture Puzzler #196

A product of the industrial revolution — cast iron — made delicate, soaring, web-like structures possible. Elegant and fireproof cast iron had its heyday during which three decades of the 19th century? What caused the decline in interest for this material?

Plain, quartersawn, and rift-sawn hardwood boards each have a distinctive look. They also respond differently to changes in relative humidity. We know that hardwoods respond by exchanging moisture with their environment. We also know that hardwoods are more dimensionally stable across the grain. Can you predict which of the three types of sawn boards (Plain, quartersawn, and rift-sawn) will expand and contract the least with changes in relative humidity?