The second astronomical marvel recorded in the Scripture narrative is the going back of the shadow on the dial of Ahaz, at the time of Hezekiah's recovery, from his dangerous illness.

It was shortly after the deliverance of the kingdom of Judah from the danger threatened it by Sennacherib king of Assyria, that Hezekiah fell "sick unto death." But in answer to his prayer, Isaiah was sent to tell him—

The narrative in the Book of Isaiah gives the concluding words in the form—

The narrative is complete as a record of the healing of king Hezekiah and of the sign given to him to assure him that he should recover; complete for all the ordinary purposes of a narrative, and for readers in general. But for any purpose of astronomical analysis the narrative is deficient, and it must be frankly confessed that it does not lie within the power of astronomy to make any use of it.

It has been generally assumed that it was an actual sundial upon which this sign was seen. We do not know how far back the art of dialling goes. The simplest form of dial is an obelisk on a flat pavement, but it has the very important drawback that the graduation is different for different times of the year. In a properly constructed dial the edge of the style casting the shadow should be made parallel to the axis of the earth. Consequently a dial for one latitude is not available without alteration when transferred to another latitude. Some fine types of dials on a large scale exist in the observatories built by Jai Singh. The first of these—that at Delhi—was probably completed about 1710 a.d. They are, therefore, quite modern, but afford good illustrations of the type of structure which we can readily conceive of as having been built in what has been termed the Stone Age of astronomy. The principal of these buildings, the Samrat Yantra, is a long staircase in the meridian leading up to nothing, the shadow falling on to a great semicircular arc which it crosses. The slope of the staircase is, of course, parallel to the earth's axis.

It has been suggested that if such a dial were erected at Jerusalem, and the style were that for a tropical latitude, at certain times of the year the shadow would appear to go backward for a short time. Others, again, have suggested that if a small portable dial were tilted the same phenomenon would show itself. It is, of course, evident that no such suggestion at all accords with the narrative. Hezekiah was now in the fourteenth year of his reign, the dial—if dial it was—was made by his father, and the "miracle" would have been reproduced day by day for a considerable part of each year, and after the event it would have been apparent to every one that the "miracle" continued to be reproduced. If this had been the case, it would say very little for the astronomical science of the wise men of Merodach-Baladan that he should have sent all the way from Babylon to Jerusalem "to inquire of the wonder that was done in the land" if the wonder was nothing more than a wrongly mounted dial.

Others have hazarded the extreme hypothesis, that there might have been an earthquake at the time which dipped the dial in the proper direction, and then restored it to its proper place; presumably, of course, without doing harm to Jerusalem, or any of its buildings, and passing unnoticed by both king and people.

A much more ingenious theory than any of those was communicated by the late J. W. Bosanquet to the Royal Asiatic Society in 1854. An eclipse of the sun took place on January 11, 689 b.c. It was an annular eclipse in Asia Minor, and a very large partial eclipse at Jerusalem, the greatest phase taking place nearly at local noon. Mr. Bosanquet considers that the effect of the partial eclipse would be to practically shift the centre of the bright body casting the shadow. At the beginning of the annular phase, the part of the sun uncovered would be a crescent in a nearly vertical position; at mid eclipse the crescent would be in a horizontal position; at the end of the annular phase the crescent would again be in a vertical position; so that the exposed part of the sun would appear to move down and up in the sky over a very small distance. It is extremely doubtful whether any perceptible effect could be so produced on the shadow, and one wholly fails to understand why the eclipse itself should not have been given as the sign, and why neither the king nor the people seem to have noticed that it was in progress. It is, however, sufficient to say that modern chronology shows that Hezekiah died ten years before the eclipse in question, so that it fell a quarter of a century too late for the purpose, and no other eclipse is available to take its place during the lifetime of Hezekiah.

But there is no reason to think that the word rendered in our Authorized Version as "dial" was a sundial at all. The word translated "dial" is the same which is also rendered "degrees" in the A.V. and "steps" in the R.V., as is shown in the margin of the latter. It occurs in the prophecy of Amos, where it is rendered "stories" or "ascensions." It means an "ascent," a "going up," a "step." Thus king Solomon's throne had six steps, and there are fifteen Psalms (cxx.-cxxxiv.)—that are called "songs of degrees," that is "songs of steps."

We do not know how the staircase of Ahaz faced, but we can form some rough idea from the known positions of the Temple and of the city of David, and one or two little hints given us in the narrative itself. It will be noted that Hezekiah uses the movement of the shadow downward, as equivalent to its going forward. The going forward of course meant its ordinary direction of motion at that time of day; so the return of the shadow backward meant that the shadow went up ten steps, for in the Book of Isaiah it speaks of the sun returning "ten degrees by which degrees it was gone down." It was therefore in the afternoon, and the sun was declining, when the sign took place. It is clear, therefore, that the staircase was so placed that the shadow went down the stairs as the sun declined in the sky. The staircase, therefore, probably faced east or north-east, as it would naturally do if it led from the palace towards the Temple. No doubt there was a causeway at the foot of this staircase, and a corresponding ascent up the Temple hill on the opposite side of the valley.

We can now conjecturally reproduce the circumstances. It was afternoon, and the palace had already cast the upper steps of the staircase into shadow. The sick king, looking longingly towards the Temple, could see the lower steps still gleaming in the bright Judean sunshine. It was natural therefore for him to say, when the prophet Isaiah offered him his choice of a sign, "Shall the shadow go forward ten steps, or back ten steps?" that it was "a light thing for the shadow to go down ten steps: nay, but let the shadow return backward ten steps." It would be quite obvious to him that a small cloud, suitably placed, might throw ten additional steps into shadow.

It will be seen that we are left with several details undetermined. For the staircase, wherever constructed, was probably not meant to act as a sundial, and was only so used because it chanced to have some rough suitability for the purpose. In this case the shadow will probably have been thrown, not by a properly constructed gnomon, but by some building in the neighbourhood. And as we have no record of the direction of the staircase, its angle of inclination, its height, and the position of the buildings which might have cast a shadow upon it, we are without any indication to guide us.

When the queen of Sheba came to visit king Solomon, and saw all his magnificence, one of the things which specially impressed her was "his ascent by which he went up unto the house of the Lord." This was "the causeway of the going up," as it is called in the First Book of Chronicles. We are told of a number of alterations, made in the Temple furniture and buildings by king Ahaz, and it is said that "the covered way for the sabbath that they had built in the house, and the king's entry without, turned he unto (margin, round) the house of the Lord, because of the king of Assyria." That is to say, Ahaz considered that Solomon's staircase was too much exposed in the case of a siege, being without the Temple enclosure. This probably necessitated the construction of a new staircase, which would naturally be called the staircase of Ahaz. That there was, in later times, such a staircase at about this place we know from the route taken by the triumphal procession at the time of the dedication of the wall of Jerusalem under Nehemiah:—

In this case there would be a special appropriateness in the sign that was offered to Hezekiah. The sign that he would be so restored, as once again to go up to the house of the Lord, was to be given him on the very staircase by which he would go. He was now thirty-eight years old, and had doubtless watched the shadow of the palace descend the staircase in the afternoon, hundreds of times; quite possibly he had actually seen a cloud make the shadow race forward. But the reverse he had never seen. Once a step had passed into the shadow of the palace, it did not again emerge until the next morning dawned.

The sign then was this: It was afternoon, probably approaching the time of the evening prayer, and the court officials and palace attendants were moving down the staircase in the shadow, when, as the sick king watched them from above, the shadow of the palace was rolled back up the staircase, and a flood of light poured down on ten of the broad steps upon which the sun had already set. How this lighting of the ten steps was brought about we are not told, nor is any clue given us on which we can base a conjecture. But this return of light was a figure of what was actually happening in the life of the king himself. He had already, as it were, passed into the shadow that only deepens into night. As he sang himself after his recovery—

But now the light had been brought back to him, and he could say—