At Tournus, on the Saône, another device was adopted to serve the same end as the Auvergne roof, but admitting of a clerestory: this was the covering of the nave with a succession of barrel-vaults at right angles to the length of the church, and supported on bold transverse arches. But I doubt whether it was ever repeated on a nave, though there are several examples of aisles thus roofed;[61] and it was, no doubt, ugly and ungainly. The Le Puy architect devised yet another plan, which combined to some extent all the others, and this was, as I have explained, a succession of domical vaults, which, while it was much lighter and more practicable (owing in part to the difference of scale) than the S. Front plan of a series of genuine cupolas, achieved, nevertheless, much of the effect that was there gained. A very small portion only of the weight of the vault exerted a direct lateral thrust, and it was possible, therefore, to erect such a roof upon a clerestory; and though the transverse arches limit the height of the building in one respect, in another there is no question that the height is apparently much increased; for in looking down the interior it is impossible ever to see the apex of any of the domes, and the vault lost behind the transverse arches gains immensely in mystery and infinity, so as to produce the effect of a larger and loftier building than the reality. But, on the other hand, the disadvantages were great: the piers between the nave and its aisles were so large as to render the aisles nearly useless; and I can hardly wonder, therefore, that the example set here was not generally, if, indeed, at all followed.