this purpose, the heat can scarcely be too great: driven snow is not whiter than the burning coal in the centre of the furnace, when it has reached its maximum of intensity.

If the Glass do not get fine by the usual time allotted, and it should become coddled or gelatinous, it never will recover, however urged by subsequent fusion. Such Glass must be ladled into water, and considered only as cullet for re-fusion, with a proportion of new materials.

The man who acts as tiseur has a substitute allowed him every other Sunday. One man only is necessary to attend the furnace while founding; but a boy, in addition, is desirable, in case of accident by broken pots, that he may be sent to procure assistance, should it be necessary; or that he may, in such cases, suddenly ladle the remaining contents of a broken pot of Glass into water, to prevent its running to waste through the bars, and checking the heat of the furnace.

Formerly, scum, or sandiva, was allowed to run off, or was taken off the surface of the pots when opened for working, on Monday mornings; but the modern relative proportions and purity of the chemical materials are so good, as seldom to render this skimming necessary.

The blowing process commences on Monday early, and ceases on Friday, in the morning, or towards noon, so that the blowers have part of Friday and the whole of Saturday, for recreation: still, it is not found that the average health or longevity of English workmen is superior to the French, who work throughout the week. Both French and English have two sets of workmen, day and night, relieving each other usually every six hours; but in some parts of the Continent,