THE RETURN OF HALLEY’S COMET IN 1910. ot 
from the sun, has a much greater effect on the period than 
would be the case in a circular orbit. Halley was quite right 
in these conclusions, and we now know that the planetary 
influences can alter the period by even more than the fifteen 
months required by the case before him; the total range is five 
years, the longest on record is seventy-nine years, four and a 
half months, between A.p. 451 and 530; the shortest is that in 
the revolution just completed, which is seventy-four years, 
five months. Making a rough allowance for the action of 
Jupiter, Halley said the comet might be expected to return to 
perihelion at the end of 1758, or the beginning of 1759; be it 
noted that this was the first time in the world’s history that the 
return of a comet had been predicted; Halley was fully con- 
scious of the new epoch in astronomy that he was opening, and 
said, “(Quo circa si secundum predicta nostra redierit iterum 
circa annum 1758, hoc primum ab homine Anglo inventum 
fuisse non inficiabitur aequa posteritas.” It is rather a curious 
commentary on these words that it is just in England that we 
find scepticism expressed as to the fulfilment of the prediction. 
The well-known Gentleman’s Magazine, in its issue for Oct., 1758, 
has these verses, which show that the writer had not even ‘taken 
the trouble to find exactly what Halley had predicted, fancying 
that he had dated the comet’s return a year earlier than he had 
actually done :— 
Comet that came in eighty-two, 
Would come, it was foretold, anew, 
Late in the last, or soon this year, 
That sees, tho’ late, none such appear 
An insignificant delay ! 
It will come yet, some sages say ; 
Tho’ it should not appear, say some 
As sure as fortune, it will come. 
Prediction, this, that bears the shape, 
To vulgar eye, of an escape ; 
Or trick of cometary learning, 
To set itself above discerning. 
Now, Mr. Urban, you must know, 
Wager was laid, a year ago, 
That it would come ; and time within 
Last year, or present, is to win. 
Should it then come, and not be seen, 
Pray, in your ancient magazine, 
To which both parties have referred, 
Let the uncommon case be heard. 
