Marking this as 'read' is a bit of a cheat, because I read about half and skimmed the rest: and how I wish I'd thought to read it in the ~10 years I've owned it, instead of picking it up ready to package and send it to a BookMoocher, and finding myself entranced!
The Floating Egg is a series of pieces (not really essays: some of them are quotations from original sources, some are fictionalised vignettes, some are straightforward historical accounts and some are collections of historical minutae) concerning geology: in particular, the geology of the North Yorkshire coast around Whitby, an area which Osborne clearly knows and loves. There are chapters on alum (the 'floating egg' of the title refers to the method of extracting alum from a solution of mineral salts: a hen's egg, placed in the mixture, would float to the surface at the moment when the liquid had reached the correct density), on meteorites, on dinosaur fossils, on Captain Cook, and on theoretical geology -- the strata that are typically found adjacent to one another in the British Isles, an understanding of which helped early geologists to earn their keep by advising mining corporations.
Each chapter stands alone, though some make strange reading taken together. It's just the right sort of book to rekindle my interest in a science of which I used to have a working knowledge (almost took Geology O-level as an additional subject, but class was Saturday mornings and I couldn't get to it). It made me want to do some serious fossil-hunting again, to walk Yorkshire beaches and pick up jet and ammonites, to revisit the Natural History and Science museums and look at old bones and ancient iron.
Shall try to BookMooch a copy ...