+-------------------------------------------------------------------------+ | No.| Description | Value of | Observed | Rise after | | | | | of |one Degree|rise, Jan. | having | Rise at | Total | | |Thermometer. | of Fahr. | 1849. |been boiled |Jan. 1850.| rise. | | | | | |for a week. | | | |----+-------------+----------+-----------+------------+----------+-------| | { | Sealed in | } | | | | | |1.{ | vacuum, | } 0·166 | 0·24 | 0·48 | 0·12 | 0·84 | | { | not boiled. | } | | | | | |----+-------------+----------+-----------+------------+----------+-------| | { | Sealed in | } | | | | | |2.{ | vacuum and | } 0·168 | 0·24 | 0·41 | 0·18 | 0·83 | | { | boiled. | } | | | | | |----+-------------+----------+-----------+------------+----------+-------| | { | Sealed with | } | | | | | |3.{ | air, not | } 0·199 | 0·20 | 0·50 | 0·20 | 0·90 | | { | boiled. | } | | | | | |----+-------------+----------+-----------+------------+----------+-------| | { |Sealed with | } | | | | | |4.{ |air, boiled. | } 0·154 | 0·06 | 0·45 | 0·13 | 0·65 | +----+-------------+----------+-----------+------------+----------+-------+ From inspection of the Table, no very remarkable difference is observable in the rising of these four instruments. No. 4 appears to have risen less during the first period, but goes along with the others afterwards. The effect of exposure to the temperature of boiling water shews that, under high temperature, the change goes on much faster than at the ordinary temperature of the air; from the Table it will be observed, that about twice the amount of change was caused by the boiling of the thermometers for a week, than had taken place between the first and second observations, a period of four months. It does not appear that the boiling of the thermometer tubes for eight days, previous to their being filled with mercury, had produced any change on the form of the bulbs; we should at least infer this from the change in their freezing points keeping pace so nearly with those which had not been boiled.