VOL. XXIX.] PHILOSOPHICAL TRANSACTIONS. 155 



1715, O. S. when it appeared much brighter than the neighbouring star :i, and 

 almost equal in magnitude to the middle star (called r, by Bayer) in the Swan's 

 neck. But in a month's time it could not be observed by the naked eye, and at 

 length not through a telescope. According to the period, in which it is said to 

 revolve, it should appear brightest in August, 17 J 5. 



Fig. 6 represents the Swan's neck, with the fixed stars next this new one, 

 with two other new stars, which within the century were observed to emerge 

 near it, of which that preceding the Swan's breast continues still visible, of the 

 5th magnitude; but that below the Swan's head, which had only been seen for 

 1 years, hitherto disappears. 



Fig. 5 represents the telescopic stars next the new one. 



Botanicum Hortense IV. — Giving an Account of some Rare Plants, observed 

 A.D. 1714, in several Gardens about London, By James Petiver, F.R.S. 

 N° 343, p. 229. 



Observations on the Total Eclipse of the Sun, lid u4pril 1715, made before the 

 Royal Society. By Dr. Edmund Halley, R. S. S. N° 343, p. 245. 



Though it be certain from the principles of astronomy, that there necessarily 

 happens a central eclipse of the sun in some part or other of the terraqueous 

 globe, about 28 times in each period of 18 years; and that of these no less 

 than 8 pass over the parallel of London, 3 of which 8 are total with continu- 

 ance : yet, from the great variety of the elements of which the calculus of 

 eclipses consist, it has so happened that since the 20th of March, 1 140, I can- 

 not find that there has been such a thing as a total eclipse of the sun seen at 

 London, though in the mean time the shade of the moon has often passed over 

 other parts of Great Britain. 



The novelty of the thing being likely to excite a general curiosity, and 

 having found, by comparing what had been formerly observed of solar eclipses, 

 that the whole shadow would fall upon England, I thought it a very proper op- 

 portunity to get the dimensions of the shade ascertained by observation ; and 

 accordingly I caused a small map of England, describing the track and bounds 

 of the shade, to be dispersed all over the kingdom, with a request to the curi- 

 ous to observe what they could about it, but more especially to note the time of 

 continuance of total darkness, as requiring no other instrument than a pendu- 

 lum clock, with which most persons are furnished, and as being determinable, 

 with the utmost exactness, by reason of the momentaneous occultation and 

 emersion of the luminous edge of the sun, the least part of which makes day. 



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