Page:Evolution of the thermometer.djvu/58

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57
SCALES FROM BOYLE TO NEWTON.

forgotten by succeeding philosophers, thus delaying greatly accurate observations of temperature.

Dalencé had anticipated Renaldini in adopting the principle of the subdivision of the interval between two determinable points, but the phenomena chosen by the Frenchman were not so reliable as those proposed by the Italian, which were afterwards adopted by Celsius.

Renaldini devised another method for graduating thermometers; he plunged the thermometer to be graduated first in mashed ice, then in a mixture of eleven parts cold water plus one of boiling water, and successively in mixtures of ten cold plus two boiling, nine cold plus three boiling, eight cold plus four boiling, and lastly in boiling water itself, marking on the scale the position of the expanding fluid at each immersion. This sounds plausible, but was shown by Wolff to be deceptive and unreliable.

Sir Isaac Newton was one of those who attacked the thermometrical problem of the age, but the scale proposed by this great genius was by no means satisfactory; he rejected alcohol as the dilating liquid and preferred "lintseed" oil; for fixed points in the scale he chose the