238 



TABLE V. 



MM. J. J. Pohl and J. Schabus have published, in the number for March, 1852, 

 of the Proceedings of the Imperial Academy of Vienna, Class of Mathematics and 

 Natural Philosophy, a set of short Thermometrical and Barometrical Reduction 

 Tables, among which is found a table for the reduction of the Old French Baro- 

 metrical Scale into the English. As this table shows slight discrepancies from the 

 one given in the following pages, it may not be out of place to state that they arise 

 from an accidental error in the equation used by MM. Pohl and Schabus in com- 

 puting their table. Adopting, as they do, Bird's value of the metre, viz. 



1 metre = 39.37062 English inches, 

 the value of the Paris line is 



1 Paris line = 0.088813 English inches. 

 But the table seems to have been computed by using the equation 



1 Paris line = 0.088823 English inches, 

 which gives, at the end of the table, 



348 lines x .088823 30.9104 English inches, 

 instead of 



348 " x .088813 = 30.9069 " " 



thus causing an error = 0.0035 



which, of course, gradually diminishes in lower numbers. 



34 



