Lake Superior

The man whose job it was to take that reading (Farnham J. Groves) couldn't get to work that morning.

He was involved in a court case concerning the salvage rights to the alien space ship he had found crashed there four months previously.

He was an employee of both the US Parks Department and the Canadian Meteorolgical Office.

Under Canadian law he was entitled to claim salvage rights on any vessels he found at the bottom of the lakes (he worked all five Great Lakes, but only four are shared by both the US and Canada).

However, under American law he was only entitled to salvage rights on any boats or ships which he found.

He was claiming that the American government was acting illegally in denying that the alien craft was a 'ship'... his attorney made the claim that all science fiction of the time called alien crafts "space ships", but the Attorney General counter-claimed that the correct term was "spaceship" - and thatword was not in the temperature-taker's terms of employment.

Expert lexicographers were called as witnesses. The US Attorney General called Mr Murdoch Kinnington, of Merriam-Websters, who backed the term 'spaceship. Mr Groves called The Duke of Wensleyday, from The Oxford English Dictionary who insisted that 'space ship' was the correct form. He also produced affadavits from Queen Victoria who stated that under the Law and Language Act of 1494 it was "the Queen's English" she was 'ye Finale and Onlie Arbtier in All Interpretations of ye Language and Her Majesties Law' and that this Act had never been repealed in the former Colonies.

The judge found in favour of Mr Groves - but only after taking a night to consider his judgment. In the meantime, the vessel (and the bodies of the 7 crew 'members' reported to have been aboard) were secretly removed from the courthouse by persons unknown and was never seen since - although there are many rumours that it is in a secret second-level basement of the Smithsonian Institute.

Mr Groves died a bankrupt as he had paid his lawyers in advance and, although he had been paid by a scrap metal merchant for the vessel, the check was stopped before he could cash it.

For the record, the temperature on October 30th 1984 had been 2.13º centigrade - in keeping with the seasonal averages over many years, and on November 1st it had risen to 11.04º centigrade. It has been speculated that this temperature rise was due to another alien craft having come to the lake seeking its crashed colleagues, as the night before he found the first vessel the lake had shown a temperature of 13.76º. No scientific theory can account for the mysterious rise in temperature.

Mr Groves, who had been the first underwater employee of the US Parks Department lost all interest in his work and sank into a depression. He was fired shortly afterwards and the Parks Department ceased co-operating with the Canadians. The Canadians paid Mr Groves a small pension and allowed him to live out his days in the small house which went with his job.

L'Universitie de Quebec continued to take the temperature recordings but refused to release them to the public to spite the US Parks Department.

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Note

This is the first time I am revealing what I am about to say. My great grandmother, Mrs Elisabeth Livotney, was Mr Grove's assistant and she took the reading on the night he was unable to take it. She recorded in her diary that "three of the lakes were remarkably similar in temprature (sic) ... Erie - 2,57; Superior - 2.59º; Michigan - 2,58. Huron and Ontario were both 2.41. I only just got to Lake Ontario in time to take the reading as I was delayed by elk on the road and an encounter with a small group of moonshiners."

(My grandmother never did learn the correct spelling of 'temperature'). I am editing her diaries for publication.

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Apology

Although the question asks for the 'precise' temperature, the best scientific instruments of the time could only give two decimal places.