92 Memoir relative to Ike Annular Eclipse of the Sun, 



the contrary, those persons who are on tlie eastern confines of 

 the umbra will see the lower limb of the moon in contact with 

 the lomer limb of the sun. Whilst, to those who are stationed 

 directly in the central path, the centres of the sun and the moon 

 will appear exactly to coincide ; and an uniform luminous ring, 

 equal in breadth to about one twenty-ninth part of the sun's dia- 

 meter, will surroimd the body of the moon*. 



As there are no two points on the face of the globe where the 

 visible appearances of any solar eclipse are exactly alike, it would 

 be an endless task to compute the phaenomena for any consider- 

 able number of places : and the usual mode, amongst astrono- 

 mers, is to give a general outline of the path of the moon's sha- 

 dow, and to calculate the particular circumstances of the eclipse 

 for the metropolis only, or for some known observatory ; which 

 calculation may be easily adapted to other parts of the kingdom. 

 The notices which are given in the various ephemerides, on this 

 point, are merely for the purpose of informing astronomers to 

 look out for, and note down these phaenomena : and the observa- 

 tions, thus made, are afterwards collected and compared together. 

 Under these circumstances the reader must not expect to fiml 

 the exact time and appearances of this eclipse computed for every 

 place on the continent. It will be sufficient for his purpose if 

 he knows at what time of the day he ought to look out for its 

 commencement ; and at what point of the sun's disc he ought to 

 fix his attention in order to observe the first point of contact. 

 The following table will show nearly these several particulars for 

 the different places therein mentioned ; and will assist the ob- 

 server in his computations for any other place within the umbra. 

 These values are deduced merely from a projection of the eclipse, 

 and are consequently given as approximations only, and by no 

 means as the exact values. For, where it is required to have 

 the time true to the nearest second, the observer must calculate 

 the phases of the eclipse for the precise spot where he happens 

 to be stationed. 



The angles from the vertex are all reckoned on the right hand 

 side of the sun ; as the moon always makes the first impression 

 on the sun's disc, on that side. 



* The sun will be elevated, on that day, above the horizon about 34 de- 

 crees, to that part of the continent, over which the centre of the moon's 

 umbra passes : consequently the increase of the moon's sumidiamctcr will be 

 about 74 seconds. 



IMace 



