26 Inqiiiry concerning the Nature of Heat, 



to every part of it. This cylinder of wood constitutes 

 a part of the wooden stand above mentioned. 



As the thermometer is placed in the axis of the cylin- 

 drical vessel, and as its bulb is just as long as the body 

 of this vessel, it is evident that it must ever indicate 

 the mean temperature of the water in the vessel, however 

 different the temperature of that water may be at differ- 

 ent 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 absolutely touch the bottom of the vessel, but it is 

 very near touching it. 



Figure i (Plate I.) will give a clear idea of this 

 instrument placed on its wooden stand, which is so con- 

 trived that the instrument 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 further illustration. The cylindrical vessel 

 is represented placed on the stand, with its thermome- 

 ter in its place. 



As, in some of the first experiments I made with this 

 instrument, I found it difficult to apply the coverings 

 which I used to the ends of the body of the instru- 

 ment, 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 almost any kind 

 of covering, and more especially coverings of various 



