180 Mr. Baity on an [Sept. 



the former of which was observed by the celebrated Colin 

 Maclaurin at Edinburgh, and the latter by the Earl of Morton 

 and Mr. Short, at Aberdour Castle, near the same place. Indeed 

 the annular appearance of the eclipse of 1737 was confined 

 principally to Scotland; and the eclipses of 1748 and 1764, 

 although visible to a great part of Europe, were not so generally 

 observed as could be wished, on account of the badness of the 

 weather ; so that we have not any very considerable degree of 

 information respecting this kind of solar eclipses. Moreover at 

 those periods the lunar tables were so defective that it could not 

 be predicted, with any degree of accuracy, where the annular 

 appearance would be visible ; so that many valuable observations 

 were probably lost on that account. This difficulty, however, is 

 in a great measure removed by late improvements, not only in the 

 lunar tables, but likewise in the analytical investigations relative 

 to the calculation of eclipses ; although the computations are 

 still very laborious and troublesome. 



Prior to the total eclipse which took place in London in the 

 year 1715, Dr. Halley published an account of the path of the 

 moon's shadow across the island of Great Britain ; and called 

 on the inhabitants to note down their observations and forward 

 them to him, in order that he might afterwards compare them, 

 and thereby correct the elements made use of in the calculation 

 of eclipses. The good effect of this measure may be seen in the 

 report which that illustrious astronomer afterwards drew up, and 

 sent to the Royal Society, and which is inserted in the Phil. 

 Trans. No. 343, vol. xxix. p. 245. Mr. Maclaurin, likewise, 

 previous to the annular eclipse in 1737, before mentioned, wrote 

 to several persons in the country, " desiring that they would 

 determine and note down the duration of the annular appearance 

 as exactly as possible, in hopes, by comparing their observa- 

 tions, to have traced more correctly the path of the centre and 

 limits of the phenomenon." And in 1748 Mr. Alexander Monro 

 (Professor of Anatomy of Edinburgh), by Mr. Short's desire, 

 wrote to all his friends in different parts of the country, to pre- 

 pare in the best manner they could for the most exact observa- 

 tion of the annular eclipse which was about to take place in that 

 year. And he regrets that he did not make this application 

 earlier ; for he remarks that had " my request of having the 

 duration of the annular appearance measured been made more 

 public before the eclipse (after Dr. Halley 's example in 1715), I 

 doubt not but I should have been able to have given a more 

 exact account of the progress of the centre of this phenomenon 

 and of its limits." M. de LTsle also, with a similar view, pub- 

 lished a notice to astronomers * in order, as he observes, 

 " exciter les curieux de FEurope, qui pourront voir Feclipse 



* divertissement aux astronomcs sur feclipse anmtlaire du soteil que Von attend It 

 25 Juitlet, 1748. It was published, however, only three months prior to the eclipse 

 taking place ; so that there was scarcely time for it to get into general circulation. 



