worth one's salt

昨日に引き続き、塩（salt）に関する表現を取り上げます。

サラリーマンが毎月いただくお給料、つまりサラリー（salary）が塩に由来しているということを知っている人は多いのではないでしょうか？

そうです、昔々、お給料というものは塩で供されていたのです。


You might think of salt as nothing more than the inexpensive stuff that tastes good sprinkled on French fries and popcorn, but in fact it’s far more than just a seasoning and has a long history as a highly prized substance. Today, there are reportedly more than 14,000 known uses for salt. Not only does the human body need it to function properly, but salt also is utilized for everything from producing chemicals to deicing roads.

Before the days of artificial refrigeration, the main method for preserving food was to treat it with salt. In this way, salt came to represent power; without it, armies couldn’t travel great distances and explorers couldn’t sail to new lands because their provisions would spoil. Throughout the ages, a variety of cultures also used this mineral in ceremonies and religious rituals. For many centuries, until salt deposits were discovered throughout the world and extraction methods improved, salt was scarce, which made it more valuable.

In some ancient societies, roads and cities developed as a result of the salt trade.

The expression to be worth one’s salt, which means you’re competent and deserve what you’re earning, is most often said to have its roots in ancient Rome, where soldiers were sometimes paid in salt or given an allowance to purchase it. The word salary is derived from the Latin “salarium,” which originally referred to a soldier’s allowance to buy salt.
(Elizabeth Nix. Where did the expression “worth one’s salt” come from? Ask History. October 15, 2014.)


そして、"worth one"s salt"という表現もまた、「給料に見合うだけの〜」という意味合いであり、ここにも塩とお給料の関連を見てとることができます。