The Hartlib Papers

           The Vse of this kalendar-Glass.

     First, it ascendeth with dry and cold Weather, and descendeth with wet, on the least change of the outward Air. Probatum est.

     Secondly, the sudden falling of the Water is a certain sign of Rain, Probatum est.

     Example: Mark where the Water standeth at night when you go to Bed, and mark it again in the next morn, an hour after Sun arise, and if it be at the same degree as it was over night, the weather will be the same, but if it either rise or fall, the weather will presently change, or within 24 hours, Probatum est.

     The figure of 1,2,3 & 4, is extream heat in Summer, at 5 and 6, not so hot, at 7 and 8, cold pleasant Air, at 9 like to freeze, at 10 a frost certainly, at 11 and 12, hard Frost, at 13 and 14, very hard freezing weather, and at 15, Boats cannot pass for Ice, but at 16, men may go on foot over the Thames, or other waters in the Countrey.

     And if the water fall to 12 or 11, snow or sleet, but if it fall to 10, the Frost breaketh certainly.

     The uncertain Motion of the water, is a sign of uncertain weather.

     So long as the water standeth at any one degree, the weather will be the same.

     You may know the temper of your body by laying your hand on the bolt head; if your body be hot, the water falleth apace, or according to the temper of your body.

     You may know the hottest or coldest Room in your House, by removing the Glass to it.