TIIK Sl'NDIAL AND THE CLOCK. 99 



The Revised \'ersioii throws light on the passage by speak- 

 ing of steps instead of degrees: "Behold I will cause the 

 shadow on the steps which is gone down on the dial of Ahaz 

 with the sun to return backward ten steps." 



ISA. XXXVIII, 8. 



The dial of x\haz, or its like is a thing by no means 

 unknown ; and such structures still exist in various parts of 

 the northern hemisphere. They are simplicity itself. A set 

 of stone steps facing the north with a gnomon of some kind 

 at the top to cast a shadow on the steps. The most obvious, 

 because the most probable and convenient form of gnomon 

 would be the obelisk with its sharply defined point. The 

 greater the sun's southern declination the longer the shadow 

 would be, and the farther it would be thrown down the steps. 

 The greater the northern declination the shorter the shadow 

 would be, and the fewer would be the steps " by which " it 

 would go down. 



And it is giving a people credit for small intelligence, 

 indeed to suppose that they would not mark the extremes and 

 be fully aware that the shadow was longest at a certain time 

 in winter ; and then turning back became shortest at a certain 

 time in summer. 



They might, however, very well have failed to note that 

 when the shadow was nearly at its longest it lengthened fast- 

 est and consequently that at that time a little lowering of the 

 point of light extended the shadow very rapidly down the 

 steps of the dial. 



This can be tried at an}- moment with a cdndle for the 

 sun, a bit of board or a book for the inclined dial, and a pin 

 for the gnomon. 



That there was a dial at Jerusalem is of record, for it is 

 spoken of as the sundial of Ahaz, and probability points to 

 its being such a one as is described, for its steps and the 

 shadow cast upon them are explicitly mentioned. 



Let ITS suppose the time to be the winter solstice at Jeru- 

 salem, te)wards noon, and the shadow on the dial of Ahaz at 



