Guest Essay by Kip Hansen
While researching for a future essay tentatively titled “Whither Original Measurement Error?”, I have been reading up on the origins of the modern meteorological thermometer. Fascinating stuff, those early scientific instrument makers and their creativity and engineering skills.
I came across an interesting little [e]book that was just the sort of thing I was looking for, written by John Henry Belville in 1850, who started work at the Royal Observatory, Greenwich, Kent, England, in 1811 as a meteorologist and was still at it 35 years later. Here I reproduce the Title Page and Preface from his book:
Included in this little volume is the following chart, which I offer here without comment for those interested in the fascinating study of the long-term Central England temperature record. This thirty-five year average, day by day, is fairly well guaranteed not to have been adjusted or modified in any way since its publication in 1850 and might have some use for comparison purposes.
* Concerning the decrease of the mean daily temperature from the 12th to the 14th of May, see Humboldt’s ‘Cosmos,’, vol. i. page 121. Bohn’s edition.
The small note under the chart was included in the book. It refers to something in the great tome: Humboldt’s COSMOS; or a Sketch of a Physical Description of the Universe. Copies are available online, but I was not able to trace the exact reference.
The full Belville book is available to read online free – albeit through Google Play’s eBook app — at:
It is a rather stiffly worded, but enjoyable, trip into the scientific past.
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Moderation Note: I would appreciate links from [any reader] to good sources for historical sources of information on expected measurement errors of meteorological thermometers in use from 1850 to present, including narrative sources of “operator error”. (Example: Several years ago, I did a Surface Station Project interview in Santo Domingo, Dominican Republic, in Spanish, on how the Stevenson Screen thermometers were read there. Acceptable expected error according to the Chief Meteorologist? +/- 1 °C)