362 Action of a Galvanic Coil on an external small Magnet. 



No. of the 

 series. 



X'. 



X'-£X r 



X'-*'X 2 . 



Y'. 



T-&Y V 



Y'-*'Y 2 . 

 



1. 



-216 



+48 



+ 46 











2. 



-240 



+46 



+ 35 



38 



- 15 



-11 



3. 



-315 



+44 



+ 26 



120 



- 23 



-14 



4. 



-450 



+41 



+ 36 



325 



- 29 



-12 



5. 



-550 



+ 11 



+ 30 



848 



- 12 



+24 



6. 



- 80 



-43 



- 18 



1480 



+ 121 



+ 80 



7. 



+ 1010 



+ 121 



+ 121 



1630 



+ 183 



(+36S) 



8. 



+2480 



+276 



+ 160 



1170 



+ 69 



+44 



9. 



-184 



+23 



+ 19 















10. 



-189 



+26 



+ 21 



41 



- 15 



-11 



11. 



-200 



+34 



+ 28 



104 



- 28 



-22 



12. 



-217 



+27 



+ 29 



212 



- 39 



-30 



13. 



-123 



( + 69) 



(+ 55) 



383 



- 22 



-15 



14. 



- 57 



-22 



- 24 



424 



- 68 



-59 



15. 



+ 100 



-36 



- 31 



436 



- 62 



-68 



16. 



+264 



-50 



- 29 



410 



- 36 



-50 



17. 



+475 



-25 



- 46 



338 



- 2 



-27 



18. 



+ 668 



-17 



- 79 



186 



+ 14 



-10 



The anomalies here presented by Nos. 7 and 13, taken in 

 connexion with those in the former comparison, seem to point to 

 errors concerned with the computing of Y 2 and observing of X'. 

 The differences X'— kX x and Y' — kY 1 between the observed and 

 calculated forces according to the hydrodynamical theory, and 

 the differences X' — k'X 2 and Y'—k'Y^ according to Ampere's 

 theory, are perhaps not greater, when compared with the values 

 of X' and Y', than might from the circumstances of the observa- 

 tions be expected. Relative to these differences it may be re- 

 marked, as before, that the hydrodynamical theory, restricted to 

 the indirect action, does not agree so well with observation as 

 the theory of Ampere. The totality, however, of the above com- 

 parisons with the former theory prove that the value of k must 

 at least be very approximately constant, and so far justify the 

 theoretical conclusion that for the case of a coil, or a magnet, 

 reduced to a line of magnetism, that factor is absolutely con- 

 stant, 



But at the same time the foregoing comparisons with Ampere's 

 theory prove that the factor k 1 is also very nearly constant, 

 although there is no a priori reason deducible from that 

 theory why this should be the case. It is worthy of remark, 

 too, that the differences between observation and calculation ex- 

 hibited above follow for the most part the same law for both 

 theories, although they depend on very different processes of 

 calculation. I cannot but regard these circumstances as confir- 

 matory of the views maintained in the foregoing essay, according 



