This book is about Lewis Carroll/Charles Dodgson as a mathematician. There were errors in the parts that I understood. So I didn't trust the other parts to help me to understand new stuff. Maybe I could have learned something about math if I'd tried harder. Or maybe I would have wasted time chasing my tail around the author's mistakes.
The book's intro points out some places where math came up in Carroll's kiddie lit. It's nice--but for this you of course want Gardner's annotated Alice books, which have the math-y stuff and the other stuff as well. Once you get past the introduction, the rest of the book is organized in fits, a nice Snarky tribute.
chapter fit is about Dodgson's childhood, concentrating on the math-y bits. He learned geometry. Good for him, I guess. The second chapter is about college life. He took exams. He did well at them. Good for him, I guess. In the third chapter, he's still an academic. He tries to teach some young kids math, tries using recreational math to keep them interested. The book seems to be looking up...
And then, there was the cipher. It was around here that I had a crisis of faith with this book.
...and he finishes the example. I'm not a master of cryptography but when I look at this encoding scheme and look at the claim "Even with the English to the cipher given, it is impossible to discover the key-word", I call bullshit. Did Dodgson claim this? Was Dodgson wrong? That would be worth pointing out in the book--but that doesn't happen. Did the book explain the encoding scheme incorrectly, and maybe the real scheme really did have a way to keep folks from learning the key? Maybe.
...two days later, Dodgson recorded that he had devised another [cipher], far better than the last:
It has these advantages.
(1) The system is easily carried in the head.
(2) The key-word is the only thing necessarily kept secret.
(3) Even one knowing the system cannot possibly read the cipher without knowing the key-word.
(4) Even with the English to the cipher given, it is impossible to discover the key-word.
This new one was his matrix cipher, which is based on the following grid:
A F L Q W B G M R X C H N S Y D I/J O T Z E K P U/V *
...Following Dodgson, let us suppose that the keyword is GROUND, known only to the sender and receiver, and that the first word of our message is SEND.
- to encode the letter S we go from G (the first letter of the keyword) to S: this is 2 places to the right and 1 place down, and we encode S as 21;
- to encode the letter E we go from R (the next letter of the keyword) to E: this is 2 places to the right and 3 places down and we encode E as 23; ...
A short while later, there's a sentence, in the context of Dodgson dispelling a rumor: "No British newspaper reports have been found that support Dodgson's account, so perhaps it was true after all..." This sentence--there were a few ways to interpret it, contradictory ways. Does he mean that British newspapers are unreliable so we should trust Dodgson? Does he mean that British newspapers are more reliable than Dodgson, so perhaps it (the rumor) was true after all? What is the author trying to tell me? Around here, I gave up on the book. I was just moving my eyes over the pages.
Maybe a good book to give to a budding nerd who liked the Alice books. On the other hand, you might do better to give that nerd The Annotated Alice.
Labels: book, mad science, puzzle scene