54 



REPORT ON 



where 



A — value of — , determined from an observation of deflection with the deflecting 



magnet at the distance r from the suspended magnet. 

 A' = value of — , determined from an observation of deflection with the deflecting 



magnet at the distance r' from the suspended magnet. 

 The following table contains all the, observed values of A and A', together with 

 the computation of the corresponding values of P. The values of A were obtained 

 from deflections at a distance of 2.0 feet : those of A' from deflections at a distance 

 of 2.5 feet. 



Date. 



- 



Log. A 



Log. A' 



Log. 

 {A-A') 



L °e- 7* 



Log 



Log. 

 \r* r') 



Log. P 



P 



October 



3°, 



1865 



9.1660 



9.1669 



6.482972 



8.5640 



8.3711 



8.1187 



8.364377 



— 0.0231 



November 



13, 



1865 



9 



0084 



9 



0094 



6.388177 



8 



4063 



8 



2135 



7 



9608 



8 



42747Z 



0.0268 



November 



1 6, 



1865 



9 



0087 



9 



0088 



5.149172 



8 



4067 



8 



2129 



7 



9629 



7 



186377 



0.0015 



November 



28, 



1865 



9 



0068 



9 



0078 



6.3989;? 



8 



4047 



8 



2IBO 



7 



959i 



8 



439877 



—0.0275 



December 



13, 



1865 



9 



0234 



9 



oi75 



7-i5 2 7 



8 



4213 



8 



22l6 



7 



9879 



9 



1649 



+ 0.1462 



December 



2 3> 



1865 



9 



0295 



9 



0317 



6.7332/2 



8 



4274 



8 



2358 



7 



9798 



8 



7534« 



—0.0567 



December 



27, 



1865 



9 



0421 



9 



0413 



6.3230 



8 



4400 



8 



2454 



7 



9978 



8 



3252 



+ 0.02II 



January 



6, 



1866 



9 



0628 



9 



0633 



6.058772 



8 



4608 



8 



2674 



8 



0163 



8 



042477 



O.OIIO 



January 



18, 



1866 



9 



°53* 



9 



0S36 



6.139972 



8 



4511 



8 



2578 



8 



0064 



8 



i335« 



O.OI36 



February 



7, 



1866 



9 



0486 



9 



°495 



6.375172 



8 



4465 



8 



2 53 6 



8 



0012 



8 



3739« 



O.O237 



March 



2, 



1866 



9 



0328 



9 



°339 



6.425072 



8 



4308 



8 



2380 



7 



9852 



8 



439877 



—O.O275 



March 



19, 



1866 



9 



°35° 



9 



0342 



6.3106 



8 



433° 



8 



2383 



7 



9907 



8 



3*99 



+ 0.0209 



March 



29, 



1866 



9 



o347 



9 



0347 



4.8740 



8 



4326 



8 



2388 



7 



9890 



6 



8850 



+ O.OOO8 



April 



7, 



1866 



9 



0367 



9 



0373 



6. 155172 



8 



4346 



8 



2414 



7 



9899 



8 



165272 



O.OI46 



April 



n» 



1866 



9 



°35 6 



9 



0360 



5.929572 



8 



4336 



8 



2401 



7 



9893 



7 



940272 



O.O087 



April 



13, 



1866 



9 



°343 



9 



0368 



6.785277 



8 



4323 



8 



2409 



7 



9842 



8 



801072 



O.0632 



April 



26, 



1866 



8 



9902 



8 



9896 



6-1515 



8 



3882 



8 



1937 



7 



9456 



8 



2059 



+ O.Ol6l 



May 



7, 



1866 



8 



9680 



8 



9704 



6.718877 



8 



3 6 59 



8 



1745 



7 



9178 



8 



801077 



O.0632 



May 



14, 



1866 



8 



9468 



8 



9544 



7.193072 



8 



3447 



8 



1585 



7 



8872 



9 



305877 



0.2022 



May 



3°, 



1866 



8 



9468 



8 



9472 



5.889072 



8 



3448 



8 



1513 



7 



9004 



7 



988677 



O.OO97 



June 



9, 



1866 



8 



9775 



8 



9817 



6.966972 



8 



3754 



8 



1858 



7 



9241 



9 



042772 



— 0.1 103 



June 



IS, 



1866 



9 



0376 



9 



0346 



6.8666 



8 



4355 



8 



2387 



7 



9970 



8 



8697 



+ 0.0741 



June 



26, 



1866 



9 



0810 



9 



0826 



6.650977 



8 



4790 



8 



2868 



8 



0324 



8 



618577 



—0.0415 



November 



1, 



1866 



9 



1991 



9 



1972 



6.8414 



8 



5971 



8 



4014 



8 



1568 



8 



6847 



+ 0.0484 



The indiscriminate mean of all the observations gives 

 P=_ 0.0166 ±0.0088 



But Peirce's criterion for the rejection of doubtful observations throws out those 

 of December 13 and May 14. Accordingly, excluding them, and taking the mean 

 of all the others, there results 



P= — 0.0155^0.0057 

 and that value I have adopted. Hence, for r = 2.0 feet, we have 



and for r — 2.5 feet 



L °g-(i-^) = o. 

 L °s-( 1 -5) = °- 



00168 



00108 



