the least dangerous positions for the places of the conduits, to be afterwards constructed for carrying off the rain water, had shown where these were to be covered and where uncovered; and had moreover contrived different outlets and apertures, whereby the force of the winds should be diminished, to the end that neither vapors nor the vibrations of the earth, should have power to do injury to the building:  all which proved the extent to which he had profited by his studies, during the many years of his residence in Rome.  When in addition to these things, the superintendents considered how much he had accomplished in the shaping, fixing, uniting, and securing the stones of this immense pile, they were almost awe-struck on perceiving that the mind of one man had been capable of all that Filippo had now proved himself able to perform.  His powers and facilities continually increased, and that to such an extent, that there was no operation, however difficult and complex, which he did not render easy and simple; of this he gave proof in one instance among others, by the employment of wheels and counterpoises to raise heavy weights, so that one ox could draw more than six pairs could have moved by the ordinary methods.  The building had now reached such a height, that when a man had once arrived at the summit, it was a very great labor to descend to the ground, and the workmen lost much time in going to their meals, and to drink; arrangements were therefore made by Filippo, for opening wine-shops and eating-houses in the cupola; where the required food being sold, none were compelled to leave their labor until the evening, which was a relief and convenience to the men, as well as a very important advantage to the work.  Perceiving the building to proceed rapidly, and finding all his undertakings happily successful, the zeal and confidence of Filippo increased, and he labored perpetually; he went himself to the ovens where the bricks were made, examined the clay, proved the quality of the working, and when they were baked he would select and set them apart, with his own hands.  In like manner, while the stones were under the hands of the stone-cutters, he would look narrowly to see that they were hard and free from clefts; he supplied the stone-cutters with models in wood or wax, or hastily cut on the spot from turnips, to direct them in the shaping and junction of the different masses; he did the same for the men who prepared the iron work; Filippo likewise invented hook hinges, with the mode of fixing them to the door-posts, and greatly facilitated the practice of architecture, which was certainly brought by his labors to a perfection that it would else perhaps never have attained among the Tuscans.