480 



Prof. A. (Schuster on the Scale- Value of 



a shape as that shown in fig. 1. But I find that, assuming 

 the bulb to be cylindrical, the pressure-coefficient gives a 



Fig. 



Fig. 2. 



thickness of 0*09 *, while on the assumption that it is spherical 

 the calculated thickness of glass is 0*076, so that the result is 

 almost the same, and we are not probably far wrong in taking 

 '08 as the approximate thickness. Taking account of this 

 value and the external volume, I find the volume of mercury 

 to be about 4 cub. centim., and from the length of one degree 

 of the stem obtain the radius of the bore approximately as 

 *009. These numbers do not lay claim to any accuracy, but 

 they are sufficient to give us an idea of the principal quantities 

 involved in the construction of this thermometer. 



As the thermometer was calibrated before graduation, the 

 distance between the divisions will give us some idea as to 

 the regularity of the bore. In Table I. the first column gives 

 the division of the thermometer, and the second, in millimetres, 

 the corresponding distance from the centre of the reservoir, 

 the third column gives the differences between the numbers 

 of the second, and the numbers of this column are therefore 

 inversely proportional to the mean area of the bore at different 

 points of the thermometer* 



* All results, unless otherwise stated, are given in centime. 



