on the
period of 10,000 years. The compilers of the _Yuen-shi_ seem not to have
had access to documents relating to this system, for they give no details
about it. Finally by order of Kubilai the astronomers _Hui-Heng_ and _Ko
Show-King_ composed a new calculation under the name of _Shou-shi-li_
which came into use from the year 1280. It is thoroughly explained in the
_Yuen-shi_. Notwithstanding the fame this system generally enjoyed, its
blemishes came soon to light. In the sixth month of 1302 an eclipse of the
sun happened, and the calculation of the astronomer proved to be erroneous
(it seems the calculation had anticipated the real time). The astronomers
of the Ming Dynasty explained the errors in the _Shou-shi-li_ by the
circumstance, that in that calculation the period for one degree of
precession of the equinox was taken too long (eighty-one years). But they
were themselves hardly able to overcome these difficulties." (_Palladius_,
pp. 51-53.)--H. C.]

[1] Besides the works quoted in the text I have only been able to consult
Gaubil's notices, as abstracted in Lalande; and the Introductory
Remarks to Mr. J. Williams's _Observations of Comets ... extracted
from the Chinese Annals_, London, 1871.

[2] _Pinnula_. The French _pinnule_ is properly a sight-vane at the end of
a traversing bar. The _transverse lines_ imply that minutes were read
by the system of our _diagonal scales_; and these I understand to have
been subdivided still further by aid of a divided edge attached to the
sight-vane; qu. a Vernier?

[3] Verbiest himself speaks of the displaced instruments thus ... "ut nova
instrumenta astronomica facienda mihi imponeret, quae scilicet more
Europaeo affabre facta, et in specula Astroptica Pekinensi collocata,
aeternam Imperii Tartarici memoriam apud posteritatem servarent,
_prioribus instrumentis Sinicis rudioris Minervae, quae jam a_
trecentis _proxime_ annis _speculam occupabant, inde amotis_.
Imperator statim annuit illorum postulatis. et totius rei curam,
publico diplomate mihi imposuit. Ego itaque intra quadriennis spatium
sex diversi generis instrumenta confeci." This is from an account of
the Observatory written by Verbiest himself, and printed at Peking in
1668 (_Liber Organicus Astronomiae Europaeae apud Sinas Restitutae_,
etc.). My friend Mr. D. Hanbury made the extract from a copy of this
rare book in the London Institu