VENUS ON THE SUNS FACE. 



357 



minutes past three," he proceeds, "when I was again at liberty to 

 continue my labors, the clouds, as if by divine interposition, were en- 

 tirely dispersed, and I was once more invited to the grateful task of 

 repeating my observations. I then beheld a most agreeable spectacle, 

 the object of my sanguine wishes, a spot of unusual magnitude and 

 of a perfectly circular shape, which had already fully entered upon 

 the sun's disk on the left, so that the edges of the sun and Venus 

 perfectly coincided, forming an angle of contact." I pass over his 

 observations, to quote his account of the feelings with which Crabtree 

 witnessed the spectacle of " Venus on the sun's face." " I had writ- 

 ten," he says, " to my most esteemed friend William Crabtree, a per- 

 son who has few superiors in mathematical learning, inviting him to 

 be present at this Uranian banquet, if the weather permitted ; and my 

 letter, which arrived in good time, found him ready to oblige me. . . . 

 But the sky was very unfavorable, being obscured during the greater 

 part of the day with thick clouds ; and, as he was unable to obtain a 

 view of the sun, he despaired of making an observation, and resolved 

 to take no further trouble in the matter. But a Httle before sunset 

 namely, about thirty-five minutes past three the sun bursting forth 

 from behind the clouds, he at once began to observe, and was grati- 

 fied by beholding the pleasing spectacle of Venus upon the sun's disk. 

 Rapt in contemplation, he stood for some time motionless, scarcely 

 trusting his own senses, through excess of joy ; for we astronomers 

 have, as it were, a womanish disposition, and are overjoyed with tri- 

 fles, and such small matters as scarcely make an impression upon 

 others ; a susceptibility which those who will may deride with impu- 

 nity, even in my own presence ; and, if it gratify them, I too will join 

 in the merriment. One thing I request : let no severe Cato be seri- 

 ously offended with our follies ; for, to speak poetically, what young 

 man on earth would not, like ourselves, fondly admire Venus in con- 

 junction with the sun, pulohritudinem divitiis conjunctam f " 



Many years passed before another transit of Venus took place. 

 This was the transit of 1761, and it affords striking evidence of the in- 

 terest with which, even at this early epoch, astronomers regarded the 

 transits of Venus, that Dr. Halley, the first Astronomer Royal, pre- 

 pared a dissertation on the subject of the transit of 1761 forty-five 

 years before it took place. Considering all the circumstances, he made 

 a very fair prediction in fact, the calculated time when Venus was to 

 be at her nearest to the middle of the sun's face was only about half 

 an hour in error, whereas the epochs first announced by our present 

 Astronomer Royal for the entrance and exit of Venus during the tran- 

 sit of 1874 were one hour and three-quarters of an hour, respectively, in 

 error. I do not propose here, however, to touch on any of the mathe- 

 matical matters dealt with by Halley, and I shall content myself with 

 quoting the remarks which he made on the importance of observing 

 Venus with due care for the sake of determining the sun's distance : 



