From what exemplar this form was conceived, or by what prototype suggested, has, in the second place, exercised speculation to a wide extent. The following are the principal opinions: 1. Theory of Warburton,--that natural groves supplied the primitive idea, the trunks, branches, and foliage of the trees being represented in the pillars, arches, and tracery of the Gothic. 2. The system of Sir James Hall,--that the whole style, in all its varieties, is but an imitation of wickerwork,--an opinion frequently, though very improperly, considered as a modification of the former: it is independent, and has been very ingeniously followed out in detail. 3. Theory of Sir Christopher Wren, remarkable at least in its propounder,--that the Free Masons were the inventors of the pointed arch. 4. Opinions of many German and Continental writers,--that this arch is but an imitation of the Egyptian and Indian pyramid. 5. Hypothesis, first incidentally proposed by Bentham, subsequently methodized and illustrated by Dr Milner, and pretty generally received,--that the intersection of semicircular arches forming intermediate pointed ones, gave the primitive model. This interlacing of arches is a common ornament in buildings of the old Gothic, already explained; it occurs frequently in relievo, and, if we recollect rightly, also with disengaged columns in several of the façades of old churches in Italy. Durham and Lincoln cathedrals, likewise ecclesiastical remains in Scotland, as Kelso Abbey, furnish examples. 6. Opinion of Mr Whittaker and others,--that pointed Architecture was known to, and practised by, the Romans, early under the imperial government. Such are the leading theories on this interesting subject; an examination of the facts would lead to a history of the ecclesiastical architecture of a great portion of Europe for upwards of three centuries. In France, the pointed arch was early introduced; but the light style of Gothic architecture was not generally carried to such perfection as in Germany and Flanders, having been sooner affected by the introduction of the Italian taste. The German style was perfected about the close of the fourteenth century, and subsequently appears to have undergone little variation, even to the middle of the sixteenth, thus retaining the elegance of the best age in the art much longer. Compared with our own, the best examples have much the same character, with lighter forms and richer tracery,--but of such examples there are fewer in proportion than with us. In Italy, the pointed arch never obtained. It is found, indeed, in Venice and Milan, and occasionally elsewhere; but the style to which it gave birth is not characteristic of Italy, where the early churches are of the old or circular, and the more modern of the mixed or Lombard style. In England, four general periods mark so many changes of Gothic.