The workmen in glass will see, that, as compared with the factories of the present day, the Venetians in their instrumentalities were subjected to many difficulties,--they were oppressed by the furnace smoke, and in no way protected from the heat of the furnace, or enabled to breathe fresh atmospheric air; in fact, the impression prevailed in those days that the external air, drawn into the glass-house, was detrimental to the business, and therefore it was most cautiously guarded against. The drawing is taken from an ancient work on glass, and although limited in the view, shows the general plan. The factory wall was conical, and rose like a large chimney, with a few windows for the admission of light. Exposed to the heat of the summer sun of Venice, and of the furnace within, neither the comfort nor health of the workman was secured. The construction of the annealing department shows two tiers of pans, the use of which must have been attended with great loss of materials. Yet, with all the perceptible inconvenience, no material change in construction was made for centuries. The same plan was adopted in France and England, and it is only within the present century that any change has taken place in the latter country. In fact, in the year 1827 an Englishman erected a glass factory on the same plan in the vicinity of New York, which, from its defective construction for this climate, soon passed out of use. The Germans, however, departed from the Venetian plan so far as to place the furnace in a large and well-ventilated building, but without a furnace-cone to carry off the heat and smoke; still a decided improvement was thus effected over the system in use in France and England. The plan referred to shows to the practical workmen of the present day the excessive waste of fuel arising from the construction of the furnace; for the same expenditure of fuel in the American furnace would melt ten times the material produced from the Venetian. It is admitted that the American glass-house is far in advance of the European ones at the present day, in the particulars of capacity, ventilation, comfort of the workmen, and economy in fuel. An impression is very prevalent that glass-making is an unhealthy occupation. It may have been thus in former times; but, as a matter of fact, no mechanical employment is more healthy. Dissipated as glass-makers have been in former days, and careless of their health as they are at present, no better evidence can be adduced to prove the _generally_ healthy character of the employment than the fact that the Glass Manufacturing Company in Sandwich, averaging in their employment three hundred hands, had not a man sick through the influence of the employment, or one die in their connection, for the space of twenty years.