OF THE UNITED STATES. 



S63 



Standartls 

 compared. 





^licrometric 

 measurement!. 



78',r60400 



r8',r6ii5o 



Ends changed to middle. 





78',r60990 

 78',r6l310 



Moan of the 

 tour results. 



Correction of 

 micmraeter. 



Pinnl vnlue 

 of the mean. 



■ r8',760962 — 0",000244 78",760718 



Mean of 



thi-rmo- 



m'-ii-rs. 



Fuhren- 



heil't 



Scale. 



30°,85 



ai*+' 78'',759030 ~ 



Mv+/ 78',r60575 



Ends clianged to middle. }>78',759777 

 Mi+l 78',759200 



Mg+i 78',760je3 



-0",000240 78',759537 



Mc+/ 78",760415 



Mj+; 78",760450 



Ends changed to middle. 

 M^+' 78",7604r5 



Mj+/ 78'',760o50 



> 78',76047iJ 



-0".000242 78',760230 



34M 



About half past eleven, the four double metre bars were 

 successively put under coniparisoti for the lirst trial of their 

 length, and tbund, by one single measurement only for eacli, 

 as follows : — 



Bar A 

 B 

 C 

 D 



78',761500 

 78 '.762275 

 78,761450 

 78,760900 



— 0",000246 78,761254 



— 0",000290 78,761985 



— 0",000245 78',76I205 



— 0',000240 78',760660 



Sum 315,046125 



—0,001021 315',045I04 



36*,1 



The sum of the four double metre bars appcarinji; slill too 

 great, the bar B, which gave a result above the otiicrs, was 

 rubbed somewhat more in the manner above stated, though 

 single, some of the butting pieces being laid on the side to 

 support tlie plane. 



s 



