The Compass Rose - Map of China: Decoding the Secrets of a Vanished Cartographer - page 99

theinformationtheyneededtogetfrompointAtopointB-orpoint Jia topoint Yi ,
asChinesewouldsay.Eachroutestartsfromaspecificport,proceedsasasequence
of compass bearings and numbers of watches that a ship should hold that bearing,
and ends at the port of destination. Compass manuals were carefully guarded craft
knowledge that was passed down within families and never leaked to outsiders.
Accordingly,nonesurvivesinitsoriginalform.Butafewcameintothepossession
ofwritersintheMingdynasty,andtheycopiedthemintootherbooks.ZhangXie's
Study of the Eastern and Western Seas is one such.
Zhang derived the data in the long central section of his book, which data he
calls 'compass knowledge', from several rutters he was able to get his hands on.
And if it was hard to acquire rutters, it was even more difficult to construe their
contents, for they were written in a telegraphic way that only experienced navig-
ators could understand. 'The old maritime compass manuals of the navigators are
all written in colloquial jargon and not easy to interpret', Zhang complains, 'so I
sortoftranslated themintoproperlanguage.Thepartsthatwerereliable andworth
recording I kept and dressed up a bit.' He also decided to reorganise the routes
into a more systematic system. The data 'being all confused and disconnected the
one from the next, I fused them into a unity. I have organised everything by route.
Where a route forks and enters a port, I have noted it as a subsidiary route going to
such-and-such a country, after which I continue on with the main route, doing the
samethingatthenextfork.'Zhangwasprettysatisfiedwiththeresult,declaring,'I
managedtofittheentireoceanontoascrollnolongerthanafoot'-ametaphorfor
hisbook(thereisnomap)-'sothatyoucanmoreorlessseeitallataglance'.The
messofreality underhishandwastransformed intoacoherent,systematic account
of all the routes around the South and East China Seas. It would have been nice
to have the original documents in all their messy reality, but we don't. But better
Zhang's version than nothing at all.
One manuscript of compass routes does survive. It is called the Laud rutter. If
Zhang's Study of the Eastern and Western Seas is a step away from an authentic
pilot's manual, the Laud rutter is half a step closer. William Laud donated this
manuscript to the Bodleian Library in 1639 (Fig. 11). That the Laud rutter and the
Selden map, each unique, should both end up in the same library seems too incred-
ible to be true. But then it is difficult to imagine where else a compass manual and
a chart of the China seas could possibly have survived except in a place removed
from the trade and politics they document. It is possible that they reached Eng-
land together, but they arrived in Oxford separately, and that is as far back as we