_Thermometer b._ _Thermometer a._
20 minutes 150 deg. 46 deg.
1 hour 30 " 101 deg. 45 deg.
2 hours 30 " 80-1/2 deg. 42 deg.
12 " 40 " 45 deg. 40 deg.

"The mean temperature of the external air to which the box was
exposed during the above period, was 42 deg., the maximum being 47 deg.,
and the minimum 37 deg..

"_Experiment No. 2._--With the same arrangement as in the preceding
case, a gallon of boiling water was introduced above the peat and
water, when the thermometer _a_, was at 36 deg.; in ten minutes it rose
to 40 deg.. The cock was then turned for the purpose of drainage, which
was but slowly effected; and, at the end of twenty minutes, the
thermometer _a_, indicated 40 deg.; at twenty-five minutes, 42 deg., whilst
the thermometer _b_, was 142 deg.. At thirty minutes, the cock was
withdrawn from the box, and more free egress of water being thus
afforded, at thirty-five minutes the flow was no longer continuous,
and the thermometer _b_, indicated 48 deg.. The mass was drained, and
permeable to a fresh supply of water. Accordingly, another gallon
of boiling water was poured over it; and, in

3 minutes, the thermometer _a_, rose to 77 deg..
5 " " fell to 76-1/2 deg..
15 " " " 70-1/2 deg..
20 " " remained at 71 deg..
1 hour 50 " " " " 70-1/2 deg..

"In these two experiments, the thermometer at the bottom of the box
suddenly rose a few degrees immediately after the hot water was
added; and it might be inferred that the heat was carried downwards
by the water. But, in reality, the rise was owing to the action of
the hot water on the thermometer, and not to its action upon the
cold water. To prove this, the perpendicular thermometers were
removed. The box was filled with peat and water to within three
inches of the top, a horizontal thermometer, _a f_, having been
previously secured through a hole made in the side of the box, by
means of a tight-fitting cork, in which the naked stem of the
thermometer was grooved. A gallon of boiling water was then