How to live underwater
QUESTION How do submarines prevent a lethal build-up of CO2?
One of the major 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 canisters of soda lime.
This compound consists of sodium hydroxide and calcium hydroxide. The soda reacts to the CO2 in the submarine’s atmosphere, trapping it and removing it from the air.
Today, the most common method is amine scrubbing, an energy intensive, 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 subs use this method, which gives them their notoriously bad smell.
A back-up method 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.
Submarines must also produce oxygen. Most of this is liberated from seawater using electrolysis machines.
Another method is a chlorate candle, or oxygen candle, containing a mix of sodium chlorate and iron powder. Once lit, it smoulders at 600c, producing sodium chloride, iron oxide and up to seven man hours of oxygen per kilogram of mixture.
Alan G. White, Skipton, N. Yorks.
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), G. K. 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 debut The Cask in 1920 seemed to mark him out for greatness.
Polite, courteous and a lover of home comforts, French used methodical steps, 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 in 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. A fanatical vegetarian, he 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, later a judge, wrote mysteries with different sleuths under the name Cyril hare. Suicide excepted (1939), A Tragedy At Law (1942) and An english Murder (1951) deserve to be read.
Chemist Alfred Walter Stewart wrote as J. J. Connington. his detectives included Superintendent Ross and Chief Constable Sir Clinton Driffield, who featured in the excellent The Sweepstake Murders.
Literary novelist C. h. B. Kitchin had forays into crime fiction with amateur sleuth Malcolm Warren.
Jonathan Wray, Ipswich, Suffolk. eDITh Mary Pargeter is best known as ellis Peters, author of the medieval crime series The Cadfael Chronicles. her first Cadfael novel, A Morbid Taste For Bones, was published in 1977.
Few realise she wrote 43 books in various genres from 1937, including a series with father and son detectives George and Dominic Felse. Death And The Joyful Woman won the Mystery Writers of America’s edgar Award in 1963.
Jane Townsend, Bridgnorth, Shropshire.
QUESTION Do other countries have an equal to Land’s End to John o’ Groats?
The 603 miles between John o’ Groats to Land’s end mentioned in the previous answer is the straight line distance taking in the Irish Sea.
Unlike other trails, it doesn’t have a prescribed route, apart from the start and finish. Distances can vary by hundreds of miles.
My son walked it in 26 days and his GPS tracker app distance was 855 miles.
Phil Alexander, Farnborough, Hants. ROUTe 66 is a 30-mile hiking trail the length of Liechtenstein.
Sandwiched between Switzerland and Austria, it is the sixth smallest country in the world. The trail is officially called the Liechtenstein Panoramaweg: it is marked as no. 66 along the way.
Stretching across Alpine mountains, it gives spectacular views of the Vorarlberg, Rhine Valley and Swiss Alps, and can be completed in two or three days.
Katie Richardson, Whitstable, Kent.
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