442 Translation of the Mohit, [Aug,, 



We have discovered many of the islands and capes mentioned by Si'di' in 

 the large manuscript chart sent round for the use of the steamer Forbes in 

 its passage up the Red Sea: but by far the greater number of islets remain 

 unnamed; and to them, with a little local inquiry, Si'di"s list might 

 doubtless be easily applied. The book is also of great service in pointing 

 out the maritime channels of Arab commerce, at the period perhaps of its 

 highest prosperity, before the Portuguese, the Dutch, and the English had 

 diverted the majority of the Europe supply to the newly discovered route 

 by the Cape of Good Hope. 



The Baron* is in hopes that the presence of sea-faring Arabs will also 

 enable us to assist him in understanding the prior and more difficult chap- 

 ters of the work, wherein is discussed the manner of " making the pole," 



(' ^j) or taking the altitude of the polar star. Here, however, we have 

 little chance of success. The present navigators have adopted the im- 

 proved methods of Europe: — they take their latitude by the sun, and 

 with the modern sextant ; and the richer merchants even provide their 

 vessels with chronometers: — not that the Arabs yet possess translated 

 tables or ephemerides hy which to work the course themselves ■ but they 

 almost universally employ an English sailing master, to whose superior 

 intelligence they implicitly confide. 



Nothing then have we been able to learn of the instrument used by the 

 early navigators in taking their latitude from the circumpolar stars ; or 

 of the measure of an arc called issabd K^^') inch, and its subdivision 

 into eight zdms \{ )j) We find however on inquiry that the latter term 

 is still applied to terrestrial measurement, and is well known to 

 nautical people of the present day as the fifth part of a geographical 

 degree, (twelve nautical miles.) Though this measure does not at all 

 accord with the sailing distances quoted by Si'di' Capudan, from well 

 known places, it will be seen presently to correspond exactly with the value 

 of the celestial inch or issabd as deduced from the internal evidence of the 

 work itself. 



The Baron Hammer in his private letter to us writes thus: " Concerning 

 the measure of |» j)J the first section of the Illrd. chapter explains as 

 follows: ' The zdm, f'j, is either the practical one, {_$ s j c i or the rheto- 

 rical, ^^"Ja^ly j The practical is one of the eight parts in which day 

 and night are divided : the rhetorical is the eighth part of an inch, £^ , in 



* It seems we erred in giving that designation to Counsellor Von Hammer in 

 JS33; but our announcement proved prophetic ; the Emperor having conferred the 

 title on him in December 1835, upon his succeeding to the little state of Hoinfeld, 

 bequeathed to him and his male descendants by the late Countess Purgstall 

 (Cranstoun). The present paper is a proof that this accession of honors will not 

 detract from the zeal of his Oriental studies. — Ed. 



f We are inclined to think that this word >, g ^a*3*fll istilahiy, is an error of the 



transcriber, and that it should be l f t^r "*' usturl&biy, appertaining to the divi- 

 sions of the astrolabe. — Ed. 



