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To promote a wider interest in the science of geology through
organised lectures, field excursions and social activities.
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The Floating Egg
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been inspired by many things. A desire to write, a love of the
countryside and coastline near Whitby, an antiquarians love of the
detail of the past and an interest in geology are among the
motivators. The importance of each motivator might be in the order in
which I put them. It is not a history of geology, although there is
lot of that in it; it is not a description of the geology of the
Whitby area, although at the end of the book I knew a lot more than
when I started. But first of all we require an explanation for the mysterious and intriguing title. It is all about Alum. My dictionary defines alum as a double sulphate of aluminium and potassium, or aluminium and ammonium with 24 molecules of water, crystallising in transparent octahedra. It is much used in the production of medicines, leather, textiles, sugar, paper, paints, matches and deodorants. Nowadays it is made by a simple chemical process but before the 1870’s it had to be produced by processing a suitable raw material. The process is one which would not get planning permission in today's world. Pile shales containing the right proportions of aluminosilicates, iron pyrite, water and carbon onto brushwood, light and leave burning for nine months. Sulphur dioxide is given off, ferrous sulphate and sulphuric acid are formed. The acid reacts with the aluminosilicates to produce aluminium sulphate. The sulphates are dissolved in water, potassium (in the form of kelp) or ammonia (in the form of urine) added. There was now a solution of alum and ferrous sulphate. How to get rid of the ferrous sulphate? Evaporate the solution so that the solution was supersaturated in alum but not in ferrous sulphate. Let cool and discard the liquid, sell the alum. But when was the liquid supersaturated in alum but not in ferrous sulphate? When a hens egg placed in the liquid floated to the surface - an early method of measuring specific gravity! The idea was a great secret but industrial espionage brought it to Whitby in about 1620. Here the 35m thick alum shales of the Toarcian section of the Lower Jurassic were eminently suitable. Piles of shale 50 foot high and 150 feet long would be hacked out of the cliffs and burned on the beaches. Newcastle, just to the north was a ready source of coal for the evaporation pans, and of the urine. (Apparently urine tankers would sail from Newcastle to Whitby - the mind boggles). Is this the justification for Newcastle Brown ale? A by product of all this activity was the finding of fossils and a long succession of large fossils have found their way to many museums from the cliffs of Whitby. Many smaller fossils were found and the author tells us that the first paper concerning the usage and importance of zone fossils was written on the rocks of the area. Other topics covered are the birth of stratigraphy, suggested by the author to have occurred to William Smith on the tower of York Minster; the fall of the Wold Cottage meteorite on the land of Major Topham whose visage decorates the book’s cover; the examination by Buckland of the hyenas of the Kirkdale cave which led to the establishment of palaeontology as a science; the changing interpretations of the Whitby fault and the landforms of the North Yorkshire Moors. The very varied contents of the book are matched by the very personal nature of the narrative. Sometimes one feels that the presentation matters more than the content. Certainly the author has a lot of fun getting into his characters. Most of the chapters are written as first person narratives by a participant - not your normal detached scientific text! All in all, well worth reading especially if you like writing and North Yorkshire. |
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