model for their own, which, when the latter perceived, he remarked, ’The next model made by this personage will be mine altogether.’  The work of Filippo was very highly praised, with the exception, that, not perceiving the staircase by which the ball was to be attained, the model was considered defective on that point.  The superintendents determined, nevertheless, to give him the commission for the work, but on condition that he should show the staircase;[5] whereupon Filippo, removing the morsel of wood which he had placed at the foot of the stair, showed it constructed as it is now seen, within one of the piers, and presenting the form of a hollow reed or blow-pipe, having a recess or groove on one side, with bars of bronze, by means of which the summit was gradually attained.  Filippo was now at an age which rendered it impossible that he should live to see the lantern completed; he therefore left directions, by his will, that it should be built after the model here described, and according to the rules which he had laid down in writing, affirming that the fabric would otherwise be in danger of falling, since, being constructed with the pointed arch, it required to be rendered secure by means of the pressure of the weight to be thus added.  But, though Filippo could not complete the edifice before his death, he raised the lantern to the height of several braccia, causing almost all the marbles required for the completion of the building to be carefully prepared and brought to the place.  At the sight of these huge masses as they arrived, the people stood amazed, marvelling that it should be possible for Filippo to propose the laying of such a weight on the cupola.  It was, indeed, the opinion of many intelligent men that it could not possibly support that weight.  It appeared to them to be a piece of good fortune that he had conducted it so far, and they considered the loading it so heavy to be a tempting of Providence.  Filippo constantly laughed at these fears, and having prepared all the machines and instruments required for the construction of the edifice, he ceased not to employ all his time in taking thought for its future requirements, providing and preparing all the minutiae, even to guarding against the danger of the marbles being chipped as they were drawn up:  to which intent the arches of the tabernacles were built within defences of woodwork; and for all beside the master gave models and written directions, as we have said.

“How beautiful this building is, it will itself bear testimony.  With respect to the height, from the level ground to the commencement of the lantern, there are one hundred and fifty-four braccia;[6] the body of the lanthorn is thirty-six braccia high; the copper ball four braccia; the cross eight braccia; in all two hundred and two braccia.  And it may be confidently affirmed that the ancients never carried their buildings to so vast a height, nor committed themselves to so great a risk as to dare a competition with the heavens, which this structure verily appears to do, seeing that it rears itself to such an elevation that the hills around Florence do not appear to equal it.  And of a truth it might seem that the heavens were envious of its height, since their lightnings perpetually strike it.  While this work was in progress, Filippo constructed many other fabrics.”