METHODS EMPLOYED IN CALIBBATION OF MEECURIAL THEllMOMETEBS. 171 



Hence, c (1') is known, from it all the other o's can be deduced, and 

 the corrections at the principal points are obtained at once from the 

 equation 



V^ (h') = HI') + H2') + +H«')- 



Table XII. gives the calculations necessary for finding the transferred 

 thread-lengths. Columns I. and II. give the positions of the lower and 

 upper ends of the thi-ead. Column III. the uncorrected thread-lengths. 

 Columns IV. and V. give the values of ^ (i' -f A i') — <b (i') and 

 <l> {u' + Au') — <j>{u'). Column VI. gives the transferred thread-length 

 obtained by adding V. to III. and subtracting IV. 



Table XIII. gives the details of the determination of all the 2's in 

 terms of c (1'). 



Column II. gives the transferred thread-lengths when the upper ends 

 lie near the principal points indicated in Column I. 



Column III. contains the values of o-.-. — <tj, r, — r,, r, — rj, and 



'4) 



r3» 



'4' 



so on. 



Column IV. contains the equations between the o's obtained as 

 above. 



In Column V. the right-hand sides are transformed so as to contain 

 Z (!') and constants only. 



Table XIII. 



Table XIV. 



The value of S (!') obtained by dividing the sum of the constants by 

 10 is found to be 120-4. 



