PHILOSOPHICAL WKITINGS OF THK LATE DR. DALTOX. 19 



The second page of the Gentleman s Diary for 1792 

 contains Mr. Dalton's account of his observations on the 

 eclipse of the sun, which happened on the 3rd of April in 

 the preceding year. He gives the latitude of Kendal as 

 "54° 20' N.; longitude, 2° 50' W.; the beginning of the 

 eclipse Oh. 9' p.m.; greatest obscuration, Ih. 34'; end of the 

 eclipse, 2h. 53' ; the duration, 2h. 44' ;" and he is of opinion 

 that ** the errors in point of time will not exceed half a 

 minute. The true noon was determined by a meridian line 

 previously made ; also by two equal altitudes of the sun the 

 same day, both agreeing to half a minute. The sun's altitude 

 was found at the end of the eclipse also, and the time of that 

 was found by calculation to agree with the clock very nearly." 

 From these observations Mr. Dalton was led to conclude that 

 the tables then in use did not give the moon's latitude 

 exactly ; but the editor remarks, that " of this it is hard to 

 judge, from observations made by those who are not in the 

 constant practice of so doing." In the mathematical depart- 

 ment he proposes one new question, and answers four in the 

 previous list. Two of these solutions are inserted at length ; 

 and, at the close of that to the prize question, the editor 

 expresses himself '* much obliged to Mr. Dalton," and others, 

 " for favouring him with the result of their labours upon this 

 difficult problem" in dynamics. His next solution to Question 

 642 belongs to the interesting subject of geometrical maxima 

 and minima ; but since the problem is not very difficult, and 

 merely relates to the construction of a triangle from given 

 data, we prefer the selection of his solution to Question 648, 

 on account of its relation to the prize question in the succeed- 

 ing number of this Diary. 



Question 648. By Mr, John Gough. ** If a given pen- 

 dulum be suspended on a pin fixed in the centre of gravity of 

 a given vessel, resting on a horizontal and perfectly smooth 

 plane, how far will the pendulum, descending from a horizon- 

 tal position, move the vessel during one whole vibration ; 



