382 



PROCEEDINGS OF TUE AMERICAN ACADEMY 



We have, therefore, 



At 0° 0. 



Th — A = —102.8 ^ 



But 



T", _ 7?^"= = _L 68.4 /x 

 T"2 — i?/2 = -f 182.1 /* 



Whence 



i?^°2 — ^ = —171.2 /x 



Rf2 — A = —284.9 /i 



Also 



a S. — A = —310.0 ,1 



But 



a S. — R,"^ = —1S9. 7 iJL 



C. S. — E,"2 = — 24.8 /i 



Whence 



i?^«2 — ^ = —170.3 fi 



i?2«2 — ^ = —285.2 /x 



At 16°.6- C. 



T"> — A = -\-lG7.0iJi 



But 



T^, — i?^«. :z= -{-170.2 fi 



Whence 



^^«2 — ^ =z —3.2 ^ 



Also 



C.S. — A = —16.6 



But 



C. ^S. — Rj"2 = —14.1 /i 



a S. — R.^2 = —17.7 IX 



Whence 



E,\_ — A = —2.5 fx 



i?/2 — ^ = -j-l.l fX 



We have therefore, finally, by combination, 



At 0° C. 

 i2i«2 + 170.7 [A = A 



i?2«2 + 285.1 11 = A 



At 160.67 C. 

 i2i«2 + 2.8 |x =- A 



i22«2 — 1.3 1* = A 



It will be observed that the relation for ^^,"2 for 16°. 67 is nearly 

 identical with that determined in 1880 and 1881. 

 For the yard we have the following final results. 

 According to 



Rogers -|- Smith 

 2 

 Chaney 



From observations 



Whence 



i?,/2 — Y =z— 1.2ix 



as. — Y = —20.7 IX 

 a^. — i2,^ = — 21.6 



B.^^. — T =4-0.9 



