114 On the Manufacture of Glass, 



the pot is now smoothed by an iron instrument, and the top of 

 it trimmed and finished. After which the whole is set aside 

 to dry — when it is thought to be sufficiently firm to sustain 

 itself, which is usually the fact in forty-eight hours, the mould 

 is removed, and the whole outside of the pol is carefully 

 dressed over. This process of smoothing and solidifying is 

 continued daily, until the pot becomes so dry and hard that 

 no impression can be made upon it. The pot is now finish- 

 ed, but it should remain six or twelve months, before being 

 used, experience proving conclusively that a pot twelve 

 months old, when put into the furnace, is much less liable to 

 break, than one that has been but recently made. The frost 

 should be carefully excluded from the room where the pots 

 are stored, as should the water in them, (of which they al- 

 ways contain some,) congeal, it would ruin them. 



We usually make our pots two feet in height, twenty inch- 

 es in diameter at the top, and sixteen inches at the bottom. 

 The bottom is two and a half inches thick, — the sides one 

 inch and a half at the top, and two inches at the bottom. 

 A pot of this size when tempered, will contain 250 lbs. of 

 glass. We ordinarily have from eighty to one hundred pots 

 in the pot room, so that there may be no necessity for using 

 new pots. When perfectly made, and of good materials, a 

 pot will last in the furnace from three to six weeks. When 

 imperfectly made or of poor clay, they are very liable to 

 burst on the side, next the centre of the furnace, and at the 

 time when the melting is nearly perfected. When this acci- 

 dent occurs, the entire contents of the pot are lost, as they 

 at once, flow into the tone of the furnace, and mix with the 

 ashes and coals, with which that part is filled. 



When a new pot is to be set, it is taken to the tempering 

 oven, and placed carefully within it. The fire under this 

 oven is then gradually raised to a bright red heat, and re- 

 tained at that point five or six hours. When the workmen 

 have finished blowing, the furnace is allowed to cool down 

 to the temperature of the oven. ' The pot is then carried 

 into it, through the stoak hole or door at its end, and placed 

 by means of a large iron bar and hooks, upon the bench di- 

 rectly under one of the rings. 



The loss arising from the failure of the pots, (which can- 

 not always be prevented,) notwithstanding that all the care 

 and skill of the most experienced and intelligent workmen 

 has been bestowed upon their manufacture, adds greatly 



