Comparators for Measures of Length. 219 



COMPARISON OF STEEL METER WITH THE STANDARD. 



Series I. Steel meter was found to be .000050 cm. too long 

 at 68.6°. 



Series II. Steel meter was found to be .000008 cm. too short 

 at 68.7°. 



On account of the doubt still remaining with regard to the 

 temperature at which the brass meter is standard, it will be 

 assumed for the present that the two standards have the same 

 length. 



Comparison of decimeter divisions of steel bar : 



B}^ applj'ing these corrections, any one of these centimeters 

 becomes a standard with reference to the standard chosen. 



The steel bar is now replaced in the water-bath, and com- 

 parison is made directly with any centimeter whose value is 

 desired. Comparing with space 2 and space 8, the error of 

 No. 12 of the above series was found to be as follows : 



