384 ANNUAL OF SCIENTIFIC DISCOVERT. 



journeys." " What! with that old watch, showing only minutes, dare you 

 talk of estimating seconds? My suspicions are already too well founded." 

 " Pardon me," was the reply, " I have also a pendulum which nearly beats 

 seconds." " Show me this pendulum," says LeVerrier. The doctor goes up 

 stairs, and brings down a silk thread, to which an ivory ball was suspended. 

 " I am anxious to see how skilfully you can thus reckon seconds." The 

 lamb acquiesces. He fixes the upper end of the thread to a nail, and after 

 the ivory ball has come to rest, he draws it a little from the vertical, and 

 counts the number of oscillations corresponding with a minute on his watch, 

 and thus proves that his pendulum beats seconds. "This is not enough," 

 replies the lion; " it is one thing that your pendulum beats seconds, but it is 

 another that you have the sentiment of the second beaten by your pendulum 

 in order that you may count the seconds in observing." " Shall I venture to 

 tell you," says the lamb, " that my profession is to feel pulses and to count 

 their pulsations? My pendulum puts the second in rny ears, and I have no 

 difficulty in counting several successive seconds." 



"This is all very well for the chapter of time," says the director; "but, in 

 order to see so delicate a spot, you require a good telescope. Have you 

 one?" "Yes, sir; I have succeeded, not without difficulty, privation, and 

 suffering, to obtain for myself a telescope. After practising much economy, 

 I purchased from M. Gauche, an artist little known, though very clever, an 

 object-glass nearly four inches in diameter. Knowing my enthusiasm and 

 my poverty, he gave me the choice among several excellent ones ; and, as 

 soon as I made the selection, I mounted it on a stand, with all its parts; 

 and I have recently indulged myself with a revolving platform, and a revolv- 

 ing roof, which will soon be in action." The lion went to the upper story, 

 and satisfied himself of the accuracy of the statement. " This is all well," 

 says he, "in so far as the observation itself is concerned; but I want to see 

 the original memorandum which you made of it." 



''It is very easj*," answered the doctor, " to say you want it; but though 

 this note was written on a small square of paper, which I generally throw 

 away or burn when it is of no further use, yet it is possible I may still find 

 it." Running with fear to his Connaissance des Temps, he finds the note of 

 the 20th March, 18-19, performing the part of a marker, and covered with 

 grease and laudanum. The lion seizes it greedily, and, comparing it wiih 

 the letter which M. Yallee had brought him, he exclaims : " But, sir, you 

 have falsified this observation; the time of emergence is four minutes too 

 late." "It is," replied the lamb. "Have the goodness to examine more 

 narrowly, and you will find that the four minutes is the error of my watch, 

 regulated by sidereal time." "This is true; but how do you regulate your 

 watch by sidereal time?" "I have a small telescope, here it is, which 

 you will find in such a state as to enable me to tell the time to a second, or 

 even to some fractions of a second." 



Satisfied on this point, LeVerrier then wished to know how he determined 

 the two angular coordinates of the points of contact, of the entry and emerg- 

 ence of the planet, and how he measured the chord of the arc which separates 

 these two points. Lescarbault told him that this was reduced to the measur- 

 ing the distances of these points from the vertical and the angles of posi- 

 tion, which he did by the systems of parallel axes we have mentioned, and 

 the divided circle of card-board placed upon his finder. 



LeVerrier next inquired if he had made any attempt to deduce the planet's 

 distance from the sun from the period of four hours which it required to 



