VOL. LXVII.] PHILOSOPHICAL TRANSACTIONS. 133 



XII. Translation of a Passage in Ebn Yuunes; with some Remarks on it. By 

 the Rev. Goorge Costard^ ALA., Vicar of Twickenham., p. 231. 

 Having, by means of the r. s., been favoured with a transcript of the Arabic 

 passage in manuscript of Ebn Younes, in the library at Leyden, I now send as 

 exact a translation of it as I can. I give it in Latin, as the former translations 

 of it were in that language, and as the numbers in the ms. by no means agree 

 with calculations made by modern tables, I have ventured to suppose that they 

 have been somehow or other altered from what they were in the original tables 

 of Ebn Younes. I have likewise ventured to suppose that the present Leyden 

 copy is a transcript of another copy, which is no very violent supposition, consi- 

 dering how long ago these observations have been made, and how long it is 

 since Ebn Younes wrote. I have likewise made no scruple to suppose that, 

 however distinct and elegant both the Arabic letters and figures are in later ma- 

 nuscripts, they were not so in those of a more ancient date, so that one might 

 easily be mistaken for another, where there is a similarity; and this mistake 

 would be the more easily committed by a person ignorant of the subject. This 

 probably was the case of all such as were hired by booksellers to transcribe ma- 

 nuscripts for sale; and for this reason, when the transcriber had made any mis- 

 take, he would not blot it out for fear of spoiling the sale of his book. There 

 is an instance of this sort in this very manuscript in the observations of the 3d 

 eclipse, which is that of the moon, as may be seen in the transcript and transla- 

 tion sent last year by Mr. Schultens. 



If what has been said be allowed me, as I hope it will not be thought too 

 much, I think I shall be able to account possibly, if not probably, for the dif- 

 ferences between the observations as set down in the manuscript, and the result 

 of the calculations by modern tables: a thing which has not been hitherto at- 

 tempted, as few who have been versed in astronomy have been acquainted with 

 the Arabic language; and those, on the other hand, who have well understood 

 Arabic, have been as little conversant with astronomy. 



What I have now advanced shall be exemplified under the first eclipse, which 

 is one of the sun. In this eclipse, according to the manuscript, at the beginning, 

 the sun's altitude was more than 15 (^) degrees, and less than l6 (^); and at 

 tlie end it was more than 33 degrees (J) and J-. But I make the sun's height 

 at the beginning 30 (!) degrees, and at the end nearly 3d ( j)). In the manu- 

 script, the digits eclipsed are said to have been 8 ( v , or a , as it is sometimes 

 written); bat I make them only a little more than 4 (j), or about 4-f. 



Whether the notation in the original manuscript of Ebn Younes was in letters 

 or arithmetical figures is uncertain; but most probably it was in the former, as 

 it is in most of the tables now extant, though composed since the admission and 

 use of arithmetical figures. On this supposition then, or that they were so in 



