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 another passage of still greater interest which I discovered in the copy of Sanctorius at Washington. Translated it reads thus: "We determine the temperature by means of our glass instrument; we ascertain the high and the low (points) after this manner: we apply snow to the bulb of the glass instrument that the water may ascend to the highest point, then we approach the flame of a candle that the water may descend to the lowest point."

This important passage shows that Sanctorius appreciated the value of fixed points for graduation, and used snow and the heat of a candle to secure extremes. The division of the stem is unknown, but he mentions in one place (to be mentioned presently) "110 degrees."

One of the most celebrated books of Sanctorius is his "Medicina statica," published at Venice in 1614, and which passed through no less than eighteen Latin editions, besides two French versions, four English, one Italian, and one German. In the first edition occur the following interesting paragraphs: "How great the ponderousness of the air is, may in the first place be gathered from greater or less weight of the dregs of alum dried before in the sun and afterwards exposed to the air in the night time.