than eight pots are objectionable, through the great loss of pots in consequence of the comparatively small size of the siege, as before explained.

The manipulatory operations of Glass-making are totally dissimilar to casting metals of any kind. Scarcely any advance in this department of the manufacture has been made for above two hundred years; and the tools then used for blowing, and shaping the various articles have been since but little improved. The reason is obvious: the formation of the infinite variety of wares produced in Flint Glass-houses, relies more upon skill, adroitness, and tact, which may be termed the main-d'œuvre of the art, than upon the ingenuity of the tools—in truth, the perfection of the product of the furnace, as regards its workmanship, depends chiefly upon the tact and intuition of the Glass-blower, avoiding as much as possible the use of tools. The more these shape the article, the more imperfections are likely to be produced by the scratching and rubbing of the iron; although this is partially avoided by the use of modern wooden charred tools. Iron tools should only be employed in the earlier process to produce the crude form, and the wooden tool used but sparingly; whilst the finishing and intermediate shaping depends chiefly upon the application of centrifugal force, by rapid hand rotation; upon the expansion given to air to widen the forms while reheating at the aperture of the furnace, technically termed "flashing;" and upon a skilful final throw.