Breathing in the deep
QUESTION How do submarines prevent lethal CO2 build-up?
ONE of the biggest challenges submariners face is creating breathable air when submerged for long periods.
Carbon dioxide (CO2) scrubbing – which removes this harmful gas – was once done chemically using soda lime in canisters.
Soda lime consists of sodium hydroxide and calcium hydroxide. The soda reacts to the CO2 in the submarine’s atmosphere, trapping it in the soda and removing it from the air.
Today, the most common method is amine scrubbing, an energyintensive, but renewable, method using monoethanolamine (MEA).
CO2-filled air is passed through MEA, which traps it in solution. The rich amine (an organic compound) is transferred to a boiler where it is heated and the CO2 is released as a gas.
The liquid amine is reused while the CO2 is stored in tanks until it can be expelled into the sea.
All nuclear submarines use this method and it helps gives them their bad smell.
A back-up is lithium hydroxide. This chemical binds rapidly with CO2, but is not reusable.
Lithium hydroxide canisters are used if there is a power cut on board. This effective, passive way of removing CO2 from the atmosphere was used on the Apollo space missions.
Alan White, Skipton, Yorkshire.
QUESTION Are there any ‘lost’ fictional detectives awaiting rediscovery?
THE interwar years are known as the Golden Age of detective fiction: Agatha Christie (Hercule Poirot and Miss Marple), Dorothy L Sayers (Lord Peter Wimsey), Margery Allingham (Albert Campion), GK Chesterton (Father Brown) and Georges Simenon (Inspector Maigret).
Yet for every one of these famous authors there were many crime writers who have been forgotten.
One was Dublin-born Freeman Wills Crofts and his Scotland Yard detective, Inspector Joseph
French. Crofts was a member of The Detection Club, which included Sayers, Christie and Chesterton. His successful debut was The Cask.
Polite, courteous and a lover of home comforts, French used methodical methods, making him a blank canvas against which the intricately plotted cases stood out. The stories were excellent, but the dull protagonist never made the leap to film and did not achieve lasting fame.
My favourite was Thorpe Hazell, an amateur sleuth created by Victor Lorenzo Whitechurch, a Church of England clergyman with a passion for railways.
Hazell was the first railway detective, whose tales featured in The Strand Magazine and The Railway Magazine before being published as books.
Whitechurch set out to make his character as dissimilar to Conan Doyle’s Sherlock Holmes as possible. Hazell was a self-effacing, but highly intelligent sleuth with an encyclopaedic knowledge of the railway system. He was a fanatical vegetarian and did bizarre physical exercises at the most surprising moments.
When Dr Richard Austin Freeman introduced forensic investigator Dr John Evelyn Thorndyke in The Red Thumb Mark in 1907, he invented a new genre, the inverted detective story.
The crime was described at the start, with the story chronicling the sleuth’s attempt to solve the mystery. Thorndyke appeared in 21 novels and 40 short stories, but suffered in comparison with Sherlock Holmes.
Alfred Alexander Gordon Clark, a barrister, and later a judge, wrote terrific mysteries with different sleuths under the name Cyril Hare. Suicide Excepted (1939), A Tragedy At Law (1942) and An English Murder (1951) still deserve to be widely read.
CHB Kitchin, an accomplished literary novelist, had forays into crime fiction with amateur sleuth Malcolm Warren.
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