xxxvi Inteoduction to the Makerstoun Observations, 1845 and 1846. 



Table 4. — continued. 



Gbttingen 

 Mean Time. 



Arc at 

 Com- 



Number 

 of 



Time 

 of one 



Tempe- 

 rature 



Gbttingen 

 Mean Time. 



Arc at 

 Com- 



Number 

 of 



Time 

 of one 



Tempe- 

 rature 





mence- 



Vibra- 



Vibra- 



of 





mence- 



Vibra- 



Vibra- 



of 





ment. 



tions. 



tion. 



Needle. 





ment. 



tions. 



tion. 



Needle. 



d. h. 

 1845. 



' 





s. 



" 



d. h. 



1846. 



' 





e. 



° 



June 10 10 



4-3 



30 



8-27 



63-0 



Feb. 4 23 



4-3 



18 



6-63 



41-7 



June 12 8 



3-7 



25 



917 



74-3 



Feb. 22 23 



3-9 



20 



701 



50-4 



June 13 9 



3-7 



20 



9-22 



74-9 



Mar. 18 22 



3-7 



25 



6-00 



30-9 



June 17 1 



4-2 



20 



7-90 



640 



Mar. 25 1 



41 



30 



6-59 



43-0 



June 27 22 



3-5 



20 



7-33 



54-0 



Apr. 26 22 



3-5 



25 



6-37 



42-2 



July 7 17 



3-6 



20 



8-05 



64-3 



May 1 23 



4-6 



20 



6-91 



54-2 



July 11 23 



2-9 



15 



7-48 



57-4 



May 18 22 



4-2 



25 



6-74 



51-9 



July 14 21 



3-8 



20 



7-35 



55-2 



May 21 9 



4-5 



25 



7-39 



60-5 



July 20 22 



3-6 



20 



7-17 



560 



May 25 8 



4-1 



20 



7-58 



63-5 



July 29 22 



3-6 



20 



7-36 



56-3 



May 26 22 



4-0 



15 



6-94 



54-8 



Aug. 10 22 



4-0 



20 



7-43 



57-8 



May 27 22 



3-7 



25 



6-85 



52-5 



Aug. 19 19 



4-3 



25 



7-20 



53-7 



May 29 9 



3-7 



20 



7-65 



65-4 



Aug. 20 1 



3-4 



20 



7-01 



53-9 



May 30 8 



31 



20 



7-62 



66-0 



Aug. 28 22 



4-4 



20 



7-96 



61-9 



June 17 20 



31 



20 



8-10 



720 



Sept. 9 22 



4-3 



20 



7-41 



57-8 



June 23 20 



3-5 



10 



6-95 



56-6 



Sept. 19 23 



40 



10 



7-01 



50-3 



June 23 23 



4-0 



10 



6-95 



56-5 



Sept. 22 21 

 Sept. 23 22 



4.6 



20 



6-74 



43-8 

 43-2 













3-6 



10 



6-56 



July 2 23 



60 



30 



10-54 



64-7 



Oct. 1 23 



4-2 



15 



6-89 



51-5 



July 3 22 



5-2 



30 



10-43 



63-3 



Oct. .5 22 



4-4 



30 



6-49 



41-7 



July 5 23 



3-8 



30 



10-47 



63-2 



Oct. 13 21 



3-5 



15 



6-98 



54-5 



July 8 22 



4-6 



25 



10-16 



56-1 



Oct. 21 23 



31 



20 



6-58 



49-2 



July 13 22 



50 



30 



10-40 



63-5 



Oct. 30 22 



3-9 



20 



6-76 



47-5 



July 19 23 



4-5 



30 



10-15 



60-7 



Nov. 3 23 



4-4 



15 



6-35 



391 



July 26 20 





30 



10-38 



62-3 



Nov. 17 22 



4-5 



20 



6-43 



42-5 



Aug. 13 22 



4-2 



30 



10-26 



59-0 



Nov. 23 22 



3-6 



15 



606 



36-2 



Sept. 14 22 



40 



26 



10-16 



61-8 



Nov. 26 22 



40 



20 



6-71 



49-7 



Oct. 5 20 



50 



26 



9-74 



56-7 



Dec. 11 23 



3-6 



18 



6-32 



40-2 



Oct. 23 22 



3-8 



15 



9-48 



46- 1 



Dec. 12 23 



4-1 



20 



603 



33-5 



Nov. 6 22 



4-8 



15 



9-68 



49-5 



Dec. 14 22 



4-1 



20 



6-36 



42-5 



Nov. 9 23 



40 



17 



9-37 



42-2 



1846. 











Dec. 1 23 



3-6 



15 



9-14 



33-3 



Jan. 8 23 



4-0 



20 



6-84 



47-5 



Dec. 2 22 



4-4 



10 



8-95 



27-5 



Jan. 25 22 



40 



18 



6-75 



47-3 













48. 1st, It has been concluded from Table 5, Introduction 1844, that after the 

 needle has been vibrated by any means through a large arc, its time of vibration 

 has been increased ; this will be apparent from the observations of vibration be- 

 fore and after April 30^ 7^ July 2i^ 18^, July 26*^ 3^, November 5^, and November 

 8*^ 21*^, 1844. On all these occasions the needle was vibrated through large arcs, 

 either from the accidental approach of iron, or from the removal of the box for a 

 short period.* 



49. 2d, It is obvious, from the observations for 1844, 1845, ai^d 1846, that 

 the time of vibration depends upon the temperature of the needle, a change of + 1° 

 of temperature causing a change of from +0^*05 to 0^*10 in the time of one vibration. 



* See Transactions of the Royal Society, Edinburgh, vol. xvi., p. 69, Table I. 



