This article is associated with In Too Deep.
Robert Cahill Henderson (aka Bob Troppo) was a Cahill from the Ekaterina Branch. He was nicknamed "Bob Troppo" (an Australian term for someone who lived in the tropics so long that he became weird). He never spoke.
Robert Cahill Henderson was known for a few things:
1. He went to jail because he tried to assassinate Mark Twain, a famous Janus Cahill descendant. Troppo smashed him on the shoulder with a cane. Talk about a strange way of trying to kill someone! It does make sense to convict him though, since the cane had a knife cleverely concealed inside it.
2. He escaped the prison in an ingenious way: he had the job of cleaning the prison floors at night, so every night he would scrape a bit of wax from the wood and kept it in his cell. After a few collections, he made a wax impression of a key with which he used to escape. This made Amy and Dan determine that he was an Ekaterina and a Cahill.
3. He was a brilliant chemist, and he was a champion of Charles Darwin's theories. He broke his engagement to one of Queen Victoria's cousins and left for the South Seas, claiming he was going to do further study on Darwin's theories. But he wasn't a naturalist. He was a chemist. This probably meant that he was collecting Clues for the Clue hunt.
4. He traveled around the islands of Indonesia until settling on one to conduct experiments. During the day of the eruption of the volcano, Krakatau, a ship was noticed heading for Batavia (Jakarta in those days), carrying a cargo full of things like Wolfram and Myrrh, two of the Clues Amy and Dan had already found. However the ship never made it to port. This information shows that Bob was indeed collecting Clues while in Indonesia, working on the Clue formula.
5. But unfortunately, the lab was destroyed in the eruption, and then Bob realized that the Clue he was missing was right underneath him all this time: Water. He became crazy.
6. We're pretty sure he lived in Coober Pedy, Australia, in an opal mine. In this mine he covered the walls with the one phrase: "Ring of Fire". In one particular spot near the ventilation shaft, he drew a volcano and the words "Take Note, Take Note, O World, To Be Honest Is Not Safe" with "Safe" inside a room-like box. This helped Amy and Dan uncover that they had to go to the island of Java, Indonesia. Java is part of the Ring of Fire.
7. He met Amelia Earhart (Madrigal) during 1937 at Coober Pedy. He sold her an opal ring.
8. He also wrote a poem which concealed the Clue: Water, as to prevent confusion in the future. Whether it's to not confuse himself or his descendants, it's not particularly clear.
According to a framed poster on the museum wall Amy and Dan described him as "a youngish man with dirty hair and a blank expression. One side of his face showed white scars from his forehead to his chin."
In this book, Amy and Dan Cahill went to Australia to uncover information about their parents' trip there. During this trip, they also uncovered various secrets about trip of "Bob Troppo". It is said that Robert Cahill Henderson was hidden in an opal mine in Coober Pedy, Australia under the alias/nickname "Bob Troppo", but he also lived in Sydney during the 1880s. He was known for being extremely close to finding all the 39 Clues finding 38, but failed when his lab was destroyed (probably by the Madrigals). He then realized that the last Clue he was missing was right underneath him all this time: Water. He was driven mad, and wrote a poem to symbolize and make sure his descendants wouldn't make the same mistake that he did. He was believed to have perished in the 1883 eruption of Krakatau, probably from the tsunamis. However, Cahills believe he escaped, but barely with his life.