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this evil, by avoiding as much as possible the opening of the 
covers or boxes to see the goods, on account of the blast of 
steam which issues out when an opening is made. I have 
twice fitted up such covers and tubes to all our dyebecks, and 
both times have been obliged to remove them. The last 
time I fitted them up I made for the front a light frame with 
canvass, and this could be raised by a cord and pulley, so as 
to allow the man to avoid the steam when he opened the 
box. 
Being dissatisfied with all the plans I had tried of getting 
rid of the vapour, I determined to try a new roof. 
Now, if all idea of the old form of roof is laid aside, and 
it is asked what it is that is really wanted, the conclusion 
will be that condensation of the vapour must be avoided ; that 
the less air admitted the better, and that the air be admitted 
under the vapour and pass with it in the same direction, out 
of the building, mixing as little as possible with it. The 
admission of air must be at the command of the foreman of 
the building, and the roof should be at such a pitch that if 
drops be condensed on it they should not fall ; but trickle 
along the spar or glass into the gutter made to receive them. 
Adjoined is a sketch of the plan which I have ultimately 
adopted to effect these objects. 
A A becks along the sides. B louvre boards which can be 
opened or shut to admit air. C C openings for escape of hot 
vapour, having the same number of feet of opening as surface 
