Thursday 16 January 2020


Time was that The Blob was constructed in real time. I'd get up early, as I do, write my piece, post it on Blogspot and leave for work. Consuming a quart of tea and two slices of toast along the way. I'd often check the Wikipedia Main Page to see if something sciencey had happened overnight or if it was a significant anniversary - Joseph Hooker's birthday, that sort of thing. Then I discovered 'scheduling' which allowed me to clock up some time-insensitive copy on the weekends or the previous evening and set it/them to launch between 7am and 8am on a future morning. Old habits die hard, and I was scanning The Wik and it flagged the 1937 20thC Fox Fire when almost the entire archive of early Fox films went up in a mighty carbon footprint. It was probably a case of spontaneous combustion because early motion picture film stock was made of nitrocellulose.

The N in Nitrocellulose [R above] is the same as the N in TNT [R below] which I've written about before. Nitrocellulose is also known as gun-cotton and it's made by soaking cotton fibres (cellulose) in nitric acid. Gun-cotton is dangerously unstable: all those oxygen atoms are ready to combine with the proximate carbons to produce carbon dioxide in a violent exothermic reaction. This was discovered in about 1846 by Christian Friedrich Schönbein, who was chemisting at home (as you did back then), spilled some nitric acid on the kitchen table and used an apron to mop up the mess. He set it to dry by the stove, where upon it vaporised with a whoomph. His wife was delighted when she came home! TNT is a bit more stable, not least because the ratio of oxygen and carbon means that external oxygen and more heat is needed to get it going. Nitrocellulose will normally deflagrate like Frau Schönbein's apron. But if confined can be persuaded to detonate - shock wave travels faster than sound so !Krak!

Mais revenons nous a nos Fox Film debacle. Fox had contracted to have built an archive at Little Ferry New Jersey. Mindful of the unique resources to be stored the building was built to be fire-proof; and it was so long as the threat was external. Insufficient attention was paid to the flammability of the material to be stored:no sprinkler system, no watchmen, no ventilation. During a July 1937 heatwave, the nitrate film spontaneously ignited and blazed through the whole facility - and indeed out of the building too with flames vomiting out of all its orifices in 100 ft sheets. Nothing of historical or cultural value survived. 40,000 reels of mostly silent film had gone up with a whooomph! The only salvage was about $2,000 worth of silver from the AgNo3 which was the light sensitive compound on that old black & white film. You have to wonder why the company chose to store but one copy of the material. They must have believed the architect and the contractor when the said Fire Proof in a loud voice. Let that be a lesson to you in your escapades on your computer -
back up early and backup often!

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