380 PROCEEDINGS OP THE AMERICAN ACADEMY 



COMPARISON OF METER W WITH BRONZE STANDARD METER 

 il/ AND STEEL STANDARD METER R^, 



iu which, designating the Metre des Archives by Aq, 



i?3 -1.2;x = A, 



The coefficient of expansion of H.^ for 1° C. in 1 metre is assumed 

 to be 17.17 /x.* The coefficient of ^3 for 1° C. is assumed to be 

 10.28 /i. At 0° C. these rehxtious become, with these coefficients, 



i?/+ 284.6 M = A, 

 R, + 170.2 y. = A, 



The values R^ — W and R.^ — W are given in divisions of the mi- 

 crometer of the microscope employed, in which 



1 div. = 0.503 /t. 



The thermometer employed is No. 8G12 Baudin, and the readings t 

 have been reduced to the Yale standard. 



The observations extend from November 15 to December 3, 1884. 



Whence 



Normal Equations. 



— 4073.9= 8a+ 59.58 6 

 —28977.3 = 59.58 a +1189.62 6 



a = —522.9 div. = -203.0 ^ 

 6 = + 1.83 div. =+ 0.92 /t 



Proceedings of the American Academy, Vol. XVIII. p. 341. 



