Page 21 - Arab Navigation in the Indian Ocean (before portuguese)_Neat

30 ARAB NAVIGATION THE NAVIGATORS AND THEIR WORKS
measurements at the culmination of al-Sharafan and an evaluation of
the bashi of the group. This last is really the most important feature,
for the value represents the height of the Pole Star above its minimum
altitude at the culmination of this mansion. Thus a correction can be
made for all Pole Star sightings if the culminating mansion is known
and if the bashi value for each mansion is remembered by the i of poetry (under Haq'a) used by Na$ir al-DIn Jusi as a mnemonic
navigator (see p. 331).
A similar description follows for most of the other mansions
although sometimes there is little to write about under some of these
headings. After the second or third mansion Ibn Majid begins to : all the other properties of stars which Ibn Majid thought unnecessary
give the auspiciousness and the astrological humour of the group .
These two features together with the date of heliacal rising, the
value of the bashi, the description of the group and the meaning of
its name are given in almost every case. But it is notable that the
bashi value is omitted for the three mansions Baida, Sa‘d al-Dhabih
and Sa'd Bui* which occur next to each other (nos. 21-3). The same
happens with Far‘ al-Mu’akhkhir, but most of the material for this ! are used for qiyas when the group in question culminates—although
mansion is included in the previous mansion which bears the same
name. Also in every case (except Far5 al-Mu’akhkhir) a list of stars
used for qiyas measurements is given sometimes with a great amount
of detail. As in the case of al-Sharafan, when the stars of the mansion
are used for qiyas measurements, this information is always given
e.g. under al-Dhira'an, Qalb, Far1 al-Muqaddam, and Batn al-Hut.
The section under Far1 al-Muqaddam is extremely long giving a
description of the uses'of the different stars of the Plough. In
addition, the important positions of the Plough, Farqadan (Little
Bear) and the Pole Star are given under the respective culminating
mansions and this includes a long digression on the theory of the
bashi under the .mansions al-$arfa, al-Nathra and al-Shula. De­
scriptions of other stars'TOo occur in odd places. The southern
Dhira1 is mentioned in detail under the heading of its fellow although
itself it is not a mansion. Mention of al-Haq'a gives rise to a de­
scription of al-Jauza (Orion)'and Simak al-Ramih occurs under
Simak al-A'zal although both of these groups appear in their own
right in the fourth faHda. Descriptions of neighbouring constel­
lations occur under several mansions and under Iklil (the Crown) a
description is given of the northern Iklil (Corona Borealis).
i Some of these groups have seasonal uses either for sailors or for
agriculturalists and these uses are sometimes mentioned (under
}
Dhira ’an, Shula, Na ‘a 5im and the Su ‘ud). • *.
Others give rise to digressions on literary subjects completely
outside the realm of navigation:.The meanings of the words Simak,
Thurayya and Zubanan . give. rise .to long sections of poetical
31
quotation and in the case of Simak to a long list of proverbs. The
story of Muhalhil and ‘Amr b. Kulthum is given in detail under
Zubanan and the war of al-Bassus with Muhalhil’s poetry occurs in
the fourth fa’ida under the Farqadan. Other poetical digressions are
given under NaVim, Qalb and Zubanan. Also of note is the line
for the lengths of time taken by each of the zodiacal signs to rise.
Finally under the last mansion (Bafn al-Hut), but inserted into
the middle of the section and not at the end, is a summary mentioning
to describe in detail.
In the fourth fa'ida, the compass rhumbs, Ibn Majid drops the
date of rising after the first two and substitutes the name of the lunar
mansion which culminates with the group mentioned. The descrip­
tion and digression on the meaning of the name is continued, but
the bashi of course is not important here, neither are the stars which
this is given in places. In its place, as most of the compass rhumb
stars are prominent, their own qiyas uses are given in great detail
and this together with theoretical or literary digressions makes the
body of the fa'ida.
Under the Pole Star we^have a long section on compass rhumbs
and a comparison of Indian Ocean methods with those of the
Egyptians (Mediterranean Sea), a description of the relations of the
Pole Star to the North Pole and a note on the lack of stars around
the South Pole and on the Magellanic clouds. Also the lexicography
of the name is given in some detail.
Theoretical discussions on abddl and “fettered” qiyas measure­
ments (see p. 328) are given under Himaran and ‘Aqrab and a
description of al-Majarra (the Galaxy) appears under Vega. Seasons
are again mentioned under Simak and under al-TIr a long theoretical
essay on the formation of winds is given. Finally most of the entries
for Thurayya and al-Ta>ir, the nearest rhumbs to the east point,
are taken up with a discussion on the tirfa (see p. 298) or rather the
irregular tirfa of a rhumb so close to the east point.
On the literary side besides the war of al-Bassus mentioned above,
the section on Thurayya contains a brief history of the Mamluke
dynasty of Egypt. _ i
The fifth fa'ida appears to be a somewhat miscellaneous collection.
It really consists of various odds and ends not placed elsewhere. The
first section deals with three star groups used as, rhumbs or rather
i rhumbs, i.e. Aldebaran and al-Mir2^m (a or £ Orionis) used for
\ rhumb north of east and \ rhumb south of. east respectively and
!
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