THE OBSERVATORY.
On our road home, about a mile and a half from the present city of Delhi, we stopped to visit the Observatory, Jantr-Mantr, a building well worthy the inspection of the traveller. The name of Jayasinha, the Rajah of Ambhere, or Jayanagar, and his astronomical labours, are not unknown in Europe; but yet the extent of his exertions in the cause of science is little known; his just claims to superior genius and zeal demand some enumeration of the labours of one whose name is conspicuous in the annals of Hindūstan. Jey-sing or Jayasinha succeeded to the inheritance of the ancient Rajahs of Ambhere in the year of Vicramadittya 1750, corresponding to 1693 of the Christian æra. His mind had been early stored with the knowledge contained in the Hindū writings, but he appears to have peculiarly attached himself to the mathematical sciences, and his reputation for skill in them stood so high, that he was chosen by the Emperor Mahommed Shah to reform the calendar, which, from the inaccuracy of the existing tables, had ceased to correspond with the actual appearance of the heavens. Jayasinha undertook the task, and constructed a new set of tables; which, in honour of the reigning prince, he named Zeej Mahommedshahy. By these, almanacks are constructed at Delhi, and all astronomical computations made at the present time.
The five observatories, which were built and finished by Jayasinha, still exist in a state more or less perfect; they were erected at Jeypoor, Matra, Benares, Oujein, and Delhi.
The next observatory, in point of size and preservation, is that at Oujein; it is situated at the southern extremity of the city, in the quarter called Jeysingpoorah, and where are still the remains of a palace of Jayasinha, who was subahdar of Malwa in the time of Mahommed Shah. The observatory at Oujein has since been converted into an arsenal and foundry of cannon.
At Matra, the remains of the observatory are in the fort which was built by Jayasinha on the banks of the Jumna.
The observatory at Delhi is situated without the wall of the city, at the distance of one mile and a quarter. It consists of several detached buildings:—
1. A large equatorial dial: its form is pretty entire, but the edges of the gnomon, and those of the circle on which the degrees were marked, are broken in several places. This is the instrument called by Jayasinha semrat-yunter (the prince of dials). It is built of stone, but the edges of the gnomon, and of the arches where the gradation was, were of white marble; a few small portions of which only remain.
2. At a little distance from this instrument, towards the north-west, is another equatorial dial; more entire, but smaller and of a different construction. In the middle stands a gnomon, which, as usual in these buildings, contains a staircase up to the top. On each side of this gnomon are two concentric semicircles, having for their diameters the two edges of the gnomon; it is evident that they represent meridians. On each side of this post is another gnomon, equal in size to the former; and to the eastward and westward of them are the arches on which the hours are marked.
3. The north wall of this building connects the three gnomons at their highest end; and on this wall is described a graduated semicircle, for taking the altitudes of bodies that lie due east, or due west, from the eye of the observer.
4. To the westward of this building, and close to it, is a wall, in the plane of the meridian, on which is described a double quadrant, having for the centres the two upper corners of the wall, for observing the altitudes of bodies passing the meridian, either to the north or south of the zenith.
5. To the southward of the dial are two buildings, named Ustuánah. They exactly resemble one another, and are designed for the same purpose, which is, to observe the altitude and azimuth of the heavenly bodies. They are two in number, on purpose that two persons may observe at the same time, and so compare and correct their observations.
These buildings are circular; and in the centre of each is a pillar, of the same height as the building itself, which is open at top. From this pillar to the height of about three feet from the bottom, proceed radii of stone, horizontally, to the circular wall of the building.
6. Between these two buildings and the great equatorial dial is an instrument called shamlah. It is a concave hemispherical surface, formed of mason work, to represent the inferior hemisphere of the heavens.
The best and most authentic account of the labours of Jayasinha for the completion of his work and the advancement of astronomical knowledge, is contained in his own preface to the Zeej Mahommedshahy; from which the following extract is a literal translation:—
“To accomplish the exalted command which he had received, he (Jey-sing) bound the girdle of resolution about the loins of his soul, and constructed here (at Delhi) several of the instruments of an observatory, such as had been erected at Samarcand, agreeably to the Musalman books: such as Zat-ul-huluck, of brass, in diameter three guz of the measure now in use (which is nearly equal to two cubits of the Koran), and Zat-ul-shobetein, and Zat-ul-suchetein, and Suds-Fukheri, and Shamlah. But finding that brass instruments did not come up to the ideas that he had formed of accuracy, because of the smallness of their size, the want of division into minutes, the shaking and wearing of their axes, the displacement of the centres of the circles, and the shifting of the planes of the instruments; he concluded that the reason why the determinations of the ancients, such as Hipparchus and Ptolemy, proved inaccurate, must have been of this kind; therefore he constructed in Dar-ul-kheláfet, Shah-Jehanabad, which is the seat of empire and prosperity, instruments of his own invention, such as Jey-per-gàs and Ram-junter, and Semrat-junter, the semi-diameter of which is eighteen cubits, and one minute on it is a barleycorn and a half, of stone and lime, of perfect stability, with attention to the rules of geometry and adjustment to the meridian, and to the latitude of the place, and with care in the measuring and fixing of them; so that the inaccuracies from the shaking of the circles, and the wearing of their axes, and displacement of their centres, and the inequality of the minutes, might be corrected.
“Thus an accurate method of constructing an observatory was established; and the difference which had existed between the computed and observed places of the fixed stars and planets, by means of observing their mean motions and aberrations with such instruments, was removed. And, in order to confirm the truth of these observations, he constructed instruments of the same kind in Sewaī Jeypoor, and Matra, and Benares, and Oujein.”
After this most interesting visit to the Observatory, we returned to Delhi.