[Illustration with caption: The view of the front of a temple, apparently a dome in the centre of four corinthian porticos bearing pediments (published by Amoretti Tav. II. B as being by Leonardo), is taken from a drawing, now at the Ambrosian Gallery. We cannot consider this to be by the hand of the master.]_ _C. Studies for a form of a Church most proper for preaching. The problem as to what form of church might answer the requirements of acoustics seems to have engaged Leonardo's very particular attention. The designation of_ "teatro" _given to some of these sketches, clearly shows which plan seemed to him most favourable for hearing the preacher's voice. Pl. XCVII, No. 1 (MS. B, 52). Rectangular edifice divided into three naves with an apse on either side, terminated by a semicircular theatre with rising seats, as in antique buildings. The pulpit is in the centre. Leonardo has written on the left side of the sketch_: "teatro da predicare" _(Theatre for preaching). MS. B, 55a (see page 56, Fig. 1). A domed church after the type of Pl. XCV, No. 1, shows four theatres occupying the apses and facing the square_ "coro" _(choir), which is in the centre between the four pillars of the dome.[Footnote 1: The note_ teatro de predicar, _on the right side is, I believe, in the handwriting of Pompeo Leoni. J. P. R.] The rising arrangement of the seats is shown in the sketch above. At the place marked_ B _Leonardo wrote_ teatri per uldire messa _(rows of seats to hear mass), at_ T teatri,_ and at_ C coro _(choir). In MS. C.A. 260, are slight sketches of two plans for rectangular choirs and two elevations of the altar and pulpit which seem to be in connection with these plans. In MS. Ash II, 8a (see p. 56 and 57. Fig. 2 and 3)._ "Locho dove si predica" _(Place for preaching). A most singular plan for a building. The interior is a portion of a sphere, the centre of which is the summit of a column destined to serve as the preacher's pulpit. The inside is somewhat like a modern theatre, whilst the exterior and the galleries and stairs recall the ancient amphitheatres. [Illustration with caption: Page 57, Fig. 4. A plan accompanying the two preceding drawings. If this gives the complete form Leonardo intended for the edifice, it would have comprised only about two thirds of the circle. Leonardo wrote in the centre_ "fondamento", _a word he often employed for plans, and on the left side of the view of the exterior:_ locho dove si predicha _(a place for preaching in)._] _D. Design for a Mausoleum.