Prologue
I
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
II
Chapter 6
Chapter 7
Chapter 8
Chapter 9
Chapter 10
III
Chapter 11
Chapter 12
Chapter 13
Chapter 14
Chapter 15
Chapter 16
Chapter 17
Extracts from a letter published in the Philosophical Transactions of the Royal Society, April 1806
Acknowledgments
