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and support the fall of the water, or to occasion the waterto be dashed into small particles, that the air may bethe more effectually extricated, its distance from the pipeseems also to require no exact adjustment. There archowever some particulars, in regard to the size of thisvessel, and the disposition of some of its parts, which ap-pear to deserve attention.

The gage, mentioned in the preceding article, will bean useful addition to it ; strewing at all times by inspec-tion the force of the blast, and thus enabling the work-man to judge whether it is sufficient for the purposesintended, and giving him notice of any failings or imper-fections that may have happened in the machine ; aswhether any air escapes through the joints or cracks, orwhether the choak or throat of the funnel is obstructed bystones or other matters brought by the stream.

All the writers I have met with, who give any accountof these kinds of blowing machines, seem to suppose thewater within and without the air vessel to be upon a level.But as the air in the air vessel is so far compressed, as tobe able to raise the water in the gage to a considerableheight, it must necessarily act with equal power on thewater below it •, and if this water can pass off freely atthe bottom, it must be depressed as much as that in thegage pipe is raised. The water within and without thevessel is exactly in the fame situation with that in thebason and pipe of the gage excepting only that theformer receives a continual supply within, which passesoff as fast on the outside. The excess of the height ofwater on the outside of the vessel, above that of the waterwithin, appears to be the very power by which the air iscompressed and driven into the furnace.

To be further satisfied of this depression of the water,

I used, for the air vessel of a small machine, a tall glass,

without