Then from the 19th Century there is an early example of a manufactured ironnail, and from the English Civil War, a solid cannon ball.
然后有一个来自19世纪的早期例子——一个工业化制造的铁钉，还有来自英国内战时期的加农炮弹。
2
"The rollercoaster is wooden and so unlike rides made from iron and steel there was always a chance of the odd nail or screw that would not be entirely flat," he said.