The periodic time of recurrence of this maximum, namely, about thirty-three years, led to eager expectancy as 1866 drew near. Hopes were then fulfilled, and another splendid display took place, of which Sir Robert Ball, who observed it, has given a graphic description in his _Story of the Heavens_. The display was repeated upon a smaller scale in the two following years. The Leonids were henceforth deemed to hold an anomalous position among meteor swarms. According to theory the earth cut through their orbit at about the same date each year, and so a certain number were then seen to issue from the radiant. But, in addition, after intervals of thirty-three years, as has been seen, an exceptional display always took place; and this state of things was not limited to one year alone, but was repeated at each meeting for about three years running. The further assumption was, therefore, made that the swarm was much denser in one portion of the orbit than elsewhere,[27] and that this congested part was drawn out to such an extent that the earth could pass through the crossing place during several annual meetings, and still find it going by like a long procession (see Fig. 20, p. 269). In accordance with this ascertained period of thirty-three years, the recurrence of the great Leonid shower was timed to take place on the 15th of November 1899. But there was disappointment then, and the displays which occurred during the few years following were not of much importance. A good deal of comment was made at the time, and theories were accordingly put forward to account for the failure of the great shower. The most probable explanation seems to be, that the attraction of one of the larger planets--Jupiter perhaps--has diverted the orbit somewhat from its old position, and the earth does not in consequence cut through the swarm in the same manner as it used to do. The other November display alluded to takes place between the 23rd and 27th of that month. It is called the _Andromedid_ Shower, because the meteors appear to issue from the direction of the constellation of Andromeda, which at that period of the year is well overhead during the early hours of the night. These meteors are also known by the name of _Bielids_, from a connection which the orbit assigned to them appears to have with that of the well-known comet of Biela.