APRON. This word is employed both in military and in shipping affairs. The A. of a I cannon is a piece of sheet-lead which covers the touch-hole, tied by two pieces of N•hite rope. In ship-building, the A. is a piece of curved timber fixed behind the lower part of the stem, and just above the foremost end of the keel; its chief use is to fortify the stem, and connect it more firmly with the keel. The name of A. is also given to the plank-flooring raised at the entrance of a dock, a little higher than the bottom, to form an abutment against which the gates may shut.
APSE (Lat. apsis), a semicircular recess usually placed at the east end of a choir or chancel of a romanesque, or what is commonly called in England an Anglo-Saxon or Anglo-Nor man church. The origin of this peculiar termination to the choir is so curious, and has been so clearly established by recent German writers, that we shall endeavor to state it in a very few words. It is well known that the heathen structure from which the early Christians borrowed the form of theft churches was not the temple, but the basilica or public hall which served at once for a market-place and a court of justice. The Basilica, for the most part, was a parallelogram, at one of the shorter sides of which, opposite to the entrance, there was a raised platform destined for the accommodation of the persons engaged in and connected with the distribution of justice. This portion of the building was the prototype of the rounded choir, to which the name of A. was given, and which is still to be seen in so many of the Rhenish churches. For the praetor's chair, which was placed in the center of this semicircular space, the altar was substituted; and the steps which led to the seat from which he dispensed justice, were destined henceforth to lead to the spot where the fountain of all justice should he worshiped. Many A.'s are to be
met with in English churches, an enumeration of which will be found in Mr. Parker's excellent glossary of architecture. But as the structure is not only much more fre quent. but continued to be used to a much later period on the continent, we shall describe it as it may still be seen in almost every little village along the banks of the Rhine. The lower part of the A. is there usually pierced by two or three round arched windows, often of irregular size and height, over which there is invariably an external gallery supported by pillars, in tile form of which the rude idea of a Roman pillar is at once apparent; and the whole is joined to the end of the nave, which rises considerably above it, by a roof in the form of the segment of a cone. Where the churches are larger, there is a complete row of windows of the same rounded form, divided by pillars similar to those by which the gallery is supported, and under them frequently a line of arches of corresponding construction, whilst one or two small and irregular holes of the same form give a scanty light to the crypt beneath. Many of the smaller churches have no aisles; and the semicircular A. forms the termination of, or rather contains the chancel. The more complete specimens of the style, however, such as the minster at I3onn, afford —with the exception of the transepts and the towers, which are later additions about the most perfect examples to be found on this side the Alps of the form of the Roman basilica, as first adapted to Christian uses. Several examples of the A. are to be seen in the earlier ecclesiastical structures of Scotland; as instances, we may mention the churches of Dahneny and Kirkliston in Linlithgowshire, and of Lenchars in Fife.