190 Remarks ati the Dudley Ohservatcrry 



Nmnber of 

 Contact. ObservationB. 



Observed Washington tim« reduced 

 to the Centre of the Earth. 



Am. Eph. 



Correction to 



Brit. N. A. 



I. 



II. 

 III. 



IV. 



6 

 15 

 11 

 10 



221' 04>n47.«8 



22 07 40.2 



5 35 26.7 



5 38 17.9 



— 45.^7 — 4'' 



— 61.8 —20 



— 124.4 —18 



— 141.7 — 35 



Means. 



— 93.4 —19.5 



It will thus be seen that Mercury was in advance of his 

 position relatively to the sun as predicted from the American 

 Ephemeris and as seen from the earth, 6''.0, or one-half his 

 own diameter ; and 1''.3 in advance of the relative position, 

 as predicted from the English almanac. What proportional 

 part of these discrepancies should be assigned to the erro- 

 neously predicted places respectively of the sun and planet, 

 it is not our province to examine. It is sufficient to remark 

 that Leverrier's later tables of Mercury containing the effect 

 of a term due to the supposed attraction of a body interior 

 to the orbit of that planet, give a satisfactory representa- 

 tion of the facts. It will also be noticed that the observed 

 interval between I and II is 172.^4 and between III and 

 lY, 171.^2, in each case agreeing closely with the quantity 

 170.^6 previously deduced, — an agreement calculated to 

 inspire confidence in th-e correctness of the mean results, 

 for the several contacts within the amounts which may be 

 anticipated from their probable errors, which are ap- 

 proximately, db l."3. 



During the afternoon, lenjoyed several brief but measura- 

 bly fine opportunities for scrutinizing the disc of Mercury. 

 I noticed no variation in the color of the disc. There did 

 not appear to be the slightest trace of spot or halo, though 

 the planet was examined with three different eye-pieces of 

 magnifying powers 200, 275 and 500 respectively. With 

 the lowest power, direct vision was employed. There 



