> In 1798, the chemist Claude Berthollet accompanied Napoleon’s military
expedition to Egypt. While visiting the Natron Lakes, a series of salt water
lakes carved from limestone, Berthollet made an observation that led him
to an important discovery. When exploring the lake’s shore Berthollet found
deposits of Na2CO3, a result he found surprising. Why did Berthollet find
this result surprising and how did it contribute to an important discovery?