Nearly 2000 years ago,as the Romans began to pull out of Scotland,they left behind a curious treasure:10 tons of nails,nearly a million of the things.The nail hoard was discovered in 1960 in a four-metre-deep pit covered by two metres of gravel.
Why had the Romans buried a million nails?The likely explanation is that the withdrawl was rushed,and they didnt want the local Caledoions getting their hands on 10 tons of weapons grade iron.The Romans buried the nails so deep that they would not be discovered for almost two millenia.
Later civilisations would value the skilled blacksmith's labour in a nail even more than the raw material.As Roma A ground explains in her new delightful book nuts and Bolts,early 17th-century Virginians would sometimes bum down their homes if they were planning to relocate.This was an attempt to recover the valuable nails,which could be reused after sifing the ashes.
The price of nails fell by 90%between the late 1700s and mid 1900s,as economist Daniel Sichel points out in a research paper.According to Sichel,although the falling price of nails was driven partly by cheaper iron and cheaper energy,most of the credit goes to nail manufacturers who simply found more efficient ways to turn steel into nails.
Nails themselves have changed over the years,but Sichel studied them because they haven't changed much
21.Romans buried the nails probably for the sake of .
22.The example of early 17th-century virginians is used to .
23.What played the major role in lowering the price of nail after the late 1700?
24.It can be learned from Paragraph 5 that nails .
25.Which of the following one best summaries the last2 paragraphs?
