80 Count Rumford’s Enquiry concerning the Nature of Heat y 
the water in the vessel, however different the temperature of 
that water may be at different depths. 
The thermometer is firmly supported in its place, by causing 
a part of the lower end of its scale to enter the neck of the 
cylindrical vessel, and to fit it with some degree of accuracy, 
but not so nicely as to be in danger of sticking fast in it. 
The lower end of the bulb of the thermometer does not ab- 
solutely touch the bottom of the vessel, but it is very near 
touching it. 
Figure 1 (Plate IV.) will give a clear idea of this instrument, 
placed on its wooden stand, which is so contrived, that the instru- 
ment may be placed higher, or lower, at pleasure. 
The foregoing description of this instrument is so particular, 
that the figure will be easily understood, without any farther 
illustration. The cylindrical vessel is represented placed on the 
stand, with its thermometer in its place. 
As, in some of the first experiments I made with this in- 
strument, I found it difficult to apply the coverings which I 
used, to the ends of the body of the instrument, I endeavoured, 
by covering up those ends with a permanent and very warm 
covering, to oblige most of the heat to pass off through the 
vertical sides of the instrument ; to which it was easy to fit al- 
most any kind of covering, and more especially coverings of 
various thicknesses of confined air, the relative warmth of 
which I was very desirous of ascertaining. 
The means I employed for covering up the ends of the in- 
strument were as follows. Having provided two thin cylindrical 
wooden boxes, (like common pill-boxes, but much larger,) 
something less in diameter than the body of the instrument, 
and 2 \ inches deep, I dried them as much as possible ; and, after 
