The structure next in importance architecturally, and as a place of amusement, would be the Hippodrome. The only illustration of this building that I shall offer is the ground plan given in the general map of the city. This gigantic structure, situated outside the south wall of the city a little west of south from the Theatre, is very difficult to see, and even more difficult to measure when found, for the reason that it is divided within by high and loosely-built garden walls, and surrounded on all sides, save for a short space on the west, by similar walls which divide the little vineyards of the natives of Bosra. It was quite possible however, by asking owners to unlock their garden gates — for the precaution of locks is necessary against Bedawin and sneak thieves — to trace, metre by metre, the entire length of the east side and the curved south end, and to secure measurements of the extreme width near the opposite ends. It was further possible to take measurements of the depth of the seating space, i. e. from the outside wall to the face of the barrier about the course, and two small groups of stone seats were discovered, one on the west side and one on the east. The extreme length is a little over 446 metres, the width, at the diameter of the cavea, 134 metres, and at the opposite end 120 metres. The measurement from the outside of the outer wall to the wall about the race course is 18.50 m. This leaves an extreme width for the course of 97 m. and an extreme length of over 400 m., at the least two stadia. It was this great length and proportional width that suggested the name of Hippodrome rather than Stadium for this structure. It is quite certain that its northern end was not curved like the southern end, and hence it could not properly be called a circus; if that detail of difference is supposed to distinguish the one from the other. It is also evident that the western wall is a little longer than the southern which is usual in these buildings. The divisions, like scalae, shown on the plan, are wholly conjectural. The structure was apparently a nearly solid mass of masonry. I could not discover any traces of an interior longitudinal vaulted passage, though there may have been one. There were apparently transverse stairways leading from the exterior to the seats and vaulted over, but this could not be definitely determined without excavations. There are remains of an arched entrance at the south end. The outer facing of the enclosing wall has been almost entirely carried away. The few stone seats that are still to be seen lying upon the sloping masonry are .68 m. deep and .45 m. high, corresponding exactly to the dimensions of the theatre seats at Philadelphia (Amman), but these are devoid of ornament and are only slightly cut under in front. Since the depth of the seating space is 18.50 m. over all, it is probable, when allowance was made for a passage below the seats and for another above them, and deducting the thickness of the wall, that there was room for about twenty tiers of seats and one praecinctio. Two rows of twenty tiers of seats each, each row a quarter of a mile long, would provide seating for a large proportion of the population of the Province of Arabia, not less-than 30,000 persons; but since the lowest seating capacity of the Circus Maximus at Rome is computed (by Dionysius) to have been 150,000, and the highest (by P. Victor) to have been 385,000, these figures do not seem improbably great. For a review of inscriptions found in Southern Syria which relate to the circus, see the commentary under inscr. 256 in Div. III.
Just west of the Theatre (castle), on the east side of a road that leads southward from the main east-and-west street (see map of city) are two heavy parallel walls of masonry the northern end of one of which is curved on the arc of a circle. If the semicircle be completed, and if the walls should be found to be a little longer, we should have here the dimensions of a stadium.