The first thing is to fix the engine in a good double furnace, so contrived that the flame of your fire may circulate round and encompass your two boilers to the best advantage, as you do coppers for brewing. Before you make any fire, unscrew _g_ and _n_, being the two small gauge-pipes and cocks belonging to the two boilers, and at the holes, fill _l_, the great boiler, two-thirds full of water, and _d_, the small boiler, quite full; then screw in the said pipes again as fast and light as possible; then light the fire at _b_. When the water in _l_ boils, the handle of the regulator, marked _z_, must be thrust from you as far as it will go, which makes all the steam rising from the water in _l_ pass with irresistible force through _o_ into _p_, pushing out all the air before it, through the clack, _r_, making a noise as it goes; and when all is gone out, the bottom of the vessel, _p_, will be very hot; then pull the handle of the regulator to you, by which means you stop _o_, and force your steam through _o_ into the _p_, until that vessel has discharged its air through the clack, _r_, up the force-pipe. In the mean time, by the steam’s condensing in the vessel _p_, a vacuum or emptiness is created, so that the water must, and will, necessarily, raise up, through _t_, the sucking-pipe, lifting up the clack, _r_, and filling the vessel, _p_. In the mean time, the vessel, _p_, being emptied of its air, turn the handle of the regulator from you again, and the force is upon the surface of the water in _p_, which surface being only heated by the steam, it does not condense it, but the steam gravitates or presses with an elastic quality like air; still increasing its elasticity or spring, till it counterpoises, or rather exceeds the weight of the water ascending in _s_, the forcing-pipe, out of which, the water in _p_ will be immediately discharged when once gotten to the top, which takes up some time to recover that power; which having once got, and being in work, it is easy for any one that never saw the engine, after half an hour’s experience, to keep a constant stream running out the full bore of the pipe, _s_; for, on the outside of the vessel, _p_, you may see how the water goes out, as well as if the vessel were transparent; for, as far as the steam continues within the vessel, so far is the vessel dry without, and so very hot, as scarce to endure the least touch of the hand; but as far as the water is, the said vessel will be cold and wet, where any water has fallen on it; which cold and moisture vanishes as fast as the steam, in its descent, takes place of the water; but if you force all the water out, the steam, or a small part thereof, going through _r_, will rattle the clack, so as to give sufficient notice to pall the handle of the regulator to you, which, at the same time, begins to force out the water from _p_, without the least alteration of the stream; only, sometimes, the