ed to the stage where one
can assert much more positively that the device was an
astronomical computer for sidereal, solar, lunar, and
possibly also planetary phenomena. (See my article in the
_Scientific American_, June 1959, vol. 200, No. 6, pp.
60-67.) Relevant to the present study, it must also be
noted at this point that the machine is now shown to be
strongly related to the geared astrolabe of al-Biruni and
thereby the Hellenistic, Islamic, and European
developments are drawn together even more tightly.

Let us now turn our attention to those civilizations which were
intermediaries, geographically and culturally, between Greece and
medieval Europe, and between both of these and China. From India there
are only two references, very closely related and appearing in the best
known astronomical texts in connection with descriptions of the
armillary sphere and celestial globe. These texts are both quite
garbled, but so far as one may understand them, it seems that the types
of spheres and globes mentioned are more akin to those current in China
than in the West. The relevant portions of text are as follows (italics
supplied):

The circle of the horizon is midway of the sphere. As
covered with a casing and as left uncovered, it is the
sphere surrounded by Lok[=a]loka [the mountain range which
formed the boundary of the universe in puranic geography].
By the application of water is made ascertainment of the
revolution of time. One may construct a sphere-instrument
combined with quicksilver: this is a mystery; if plainly
described, it would be generally intelligible in the
world. Therefore let the supreme sphere be constructed
according to the instruction of the preceptor [guru]. In
each successive age this construction, having become lost,
is, by the Sun's favour, again revealed to some one or
other, at his pleasure. So also, one should construct
instruments in order to ascertain time. When quite alone,
one should apply quicksilver to the wonder-causing
instrument. By the gnomon, staff, arc, wheel, instruments
for taking the shadow of various kinds.... By
water-instruments, the vessel, by the peacock, man,
monkey, and by stringed sand-receptacles one may determine
time accurately. Quicksilver-holes, water, and cords, and
oil and water, mercury and sand are used in these: these
applications, too, are difficult.

_S[=u]rya Siddh[=a]nta_, xiii, 15-22,