262 Tables of the Planet Venus. 



arrangement of astronomical Tables, it was resolved to remodel 

 these entirely, and to present them in the form which, it is pro- 

 bable, the author himself would have chosen, had their construc- 

 tion been deferred to the present time. 



Daussv's Tables of Vesta were adopted as the model, which 

 has been deviated from only in two instances. The first regards 

 the mode of compensating for the intercalary day in Leap Year : 

 the one here employed, the writer believes to be new, and flatters 

 himself it may be considered an improvement, since the precept 

 usually subjoined to the table of daily motions, is liable to escape 

 notice. In the other instance, he has chosen to retain in its 

 original form the Table of Heliocentric Latitude, instead of 

 giving the Polar distances as is now commonly done. 



The chief variations from the original Tables are as follow : 

 InTable IL the epochs for 1750, 1770, 1801—1809, and 1890, 

 are omitted, and those for 1740, 1821 — 1839, and 1900 intro- 

 duced ; the whole being adapted for the meridian of Greenwich, 

 in lieu of that of Paris. And in order that the new Table might 

 not be less accurate than the old one (even by the tenth of a se- 

 cond), the computations for the mean longitude were made from 

 the original elements, and were carried to two decimal place? 

 further than are retained. The place of the perihelion is substi- 

 tuted for that of the aphelion ; and the longitude both of that, 

 and of the planet, is diminished by one degree, which is the sum 

 of the constant quantities employed to render always additive, 

 the equation of the centre, the perturbations in longitude, and 

 the reduction to the ecliptic. The longitude of the node is only 

 diminished bv four minutes, which is the constant quantity for 

 the reduction. In Table III. double quantities are given for 

 January and February, and those for the other months are in- 

 creased bv one dav's motion ; the numbers in Table IV. being 

 diminished by the like quantity. The differences in Tables VI. 

 VI 11. and X. are for 10 minutes instead of one degree. The 

 equations of perturbation are all put into one Table, whereby 

 room is saved, and reference facilitated. Lastly, the numbers 

 in Table VIII. are diminished by 0000401, sum of the con- 

 stant quantities for the perturbation of the radius vector. 



Although to persons accustomed to the use of astronomical 

 Tables, the preceding explanations will suffice, yet as short pre- 

 cepts, and an example of their application, may be acceptable 

 to many of the readers of the Philosophical Magazine, it is pro- 

 posed to supply these in a future Number. 



TABLIt 



