Page:Evolution of the thermometer.djvu/52

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51
SCALES FROM BOYLE TO NEWTON.

melting-point of butter; the space between them to be divided equally and the centre to be marked "temperate." Then each space above and below "temperate" to be divided into ten equal degrees, four additional degrees to be placed above the melting-point of butter and four below the freezing-point of water, making a scale of thirty degrees in all.

Dal. Fahr.
Melting butter … 10 86°
Medium … 0
Freezing temperature … −10 32°

He further proposed another standard scale, the fixed points to be the temperature of a cellar and of ice, the space between to be divided into fifteen degrees; and he added: "all thermometers made by the latter method are comparable." To make instruments easy of transportation, and for fancy, the stems were bent into circular, oval, spiral, triangular, and stellate shapes, and Dalencé gives figures of each. He also described the floating glass bulbs of. Kircher, and made them in the shape of turtles to apply to the arms and body of feverish persons. "Some curieux" he says, "use mercury in thermometers," but the instrument he writes of was an air-thermoscope and the fluid metal was not employed on account of its prop-