C67 The Brightest Molluscs

In a week's time, Darwin bought these materials from a chemical shop: water-soluble rice paper, water-soluble plastic film, narrow mouth glass bottle, double-sided rubber band, soft leather chain, etc.

The hardest thing to get is perchloric acid.

As one of the six strong inorganic acids, perchloric acid is more corrosive than sulfuric acid and can be diluted by water