OBSERVATIONS WITH THE ZENITH TELESCOPE. 



321 





Micrometer 



nfl — n/% 



Observed dif. 



V 

 C-0 





1 



19 — 33 



— 168 



— 3*64 



+ .53 





2 



18 — 32 



— 140 



— 2.29 



— .30 





3 



17 — 31 



— 112 



— 2.23 



+ .16 





4 



10 — 30 



— 84 



— 1.04 



— .51 



51 Cephei and 



5 



15 — 20 



— 50 



— 1.24 



+ .20 



<5 Ursa; Minoris. 



6 



14 — 28 



— 28 



— .67 



+ .15 





7 



13-27 



— 



+ .36 



— .36 





8 



12 — 26 



+ 28 



4- .88 



— .36 





9 



11 — 25 



+ 56 



-|- .04 



+ .10 





10 



10 — 24 



+ 84 



+ 1.82 



— .27 





11 



— 23 



+ 112 



+ 2.29 



— .22 





12 



8 — 22 



+ 140 



+ 2.41 



+ .18 





18 



7 — 21 



1 168 



+ 2.36 



+ .75 





1 



19 — 33 



— 168 



— 1.70 



— .13 





2 



17 — 31 



— 112 



— 1.34 



+ -12 





3 



15 — 20 



— 56 



— .71 



+ .10 



43 Cephei and 



4 



13 — 27 



— 



+ .20 



— .20 



Groombridgo 750. 



5 



11—25 



+ 56 



+ .51 



+ .10 





C 



9 — 23 



+ 112 



+ 1.22 



— .00 





7 



7 — 21 



+ 168 



+ 1.82 



+ .01 





The " observed difference " is the observed value of p (n 2 — w' 2 ). 

 The time required for 51 Cephei to pass over a space equal to one revolution is 57 s .06. 

 That for 750 Grooinbridge 40.92. Therefore, 



From 51 Cephei and 8 Ursa; Minoris p = + '.01855 = + .000325 JR 

 43 Cephei and 750 Groombridge + .01080 = + .000205 B 



Mean + .000295 R 

 Which is the value employed in this series. 



The corresponding corrections in terms of screw revolutions follow : 



7 



and 33 



+.0499 



8 



32 



.0425 



9 



31 



.0357 



10 



30 



.0295 



11 



29 



.0239 



12 



28 



.0189 



13 



27 



.0145 



14 



26 



.010(1 



15 



25 



.0074 



16 



24 



.0047 



17 



23 



.0027 



18 



22 



.0012 



19 



21 



.0003 



A preliminary reduction of the latitude observations is now carried out, applying 



