Page:Evolution of the thermometer.djvu/27

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Libri (Histoire des sciences mathématiques en Italie, Vol. IV, p. 471, notes), to describe a thermoscope independent of atmospheric pressure. The instrument is said to consist of a bulb with a neck a foot or more long, nearly filled with water into which a smaller bulb-tube was inverted so that the neck was beneath the surface; Libri's account is accompanied by a drawing that does not correspond with the description and is obviously incorrect; whether the figure is from Telioux' manuscript does not appear, but if it is of the date 1611, it is the earliest representation of a thermometer with scale known to me. The scale attached to each side of the stem is divided into eight large spaces, and each space into sixty smaller ones, a division probably suggested by the graduation of astronomical instruments into degrees and minutes.

According to Poggendorff , Salomon de Caus, whose name is associated with the use of steam as a mechanical power, described a very imperfect thermometer in the work "Raisons des forces mouvantes," published at Frankfurt in 1615.

The eminent Englishman, Lord Chancellor Bacon, is sometimes put forward as the inven-