A Practical Manual On Sea Water Distillation
With A Description Of The Necessary Machinery For The Process

42 SEA WATER DISTILLATION. imparted (after heating the water up to its boiling point) was carried off by the steam into space. It is also clear that the steam (S), having a tempera- ture of 266°, was presented to the surface of the partition under the water, and the steam thus continually supplied to replace what was liquefied, at the same time continu- ally giving up its latent heat of 927 B.T.U. until the whole of the 1 lb. of water (W) was converted into steam, which required 966 B.T.U. It is also dear that the steam (S), by giving up its latent heat as above described, and be- coming water, escaped at 0 with a temperature of 266° still left in it. 16. To carry this point a little further still. Suppose the vessel is closed at the top, so as to enable a pres- sure being exerted inside the vessel (an outlet for such pressure steam being provided on the cover, controlled if required by a valve or cock). Suppose, also, provision is made for feeding water into the vessel, as it is gradually boiled away ; and, lastly, suppose that the vessel is provided with a coil or worm placed inside, and the interior of the coil supplied with pressure steam. 17. Fig. 4 shows the apparatus now referred to, which may be recognised as a crude design of an ordinary evaporator, with a coil. C is the steam inlet to coil, E is the escape for the vapour, A is the feed inlet for replacing the water as it is gradually boiled away, B is the outlet for the brine, and D is for the discharge of the condensed steam from inside the coils, and F is the steam-room. 18. Suppose, now, the new steam generated inside the vessel, usually called secondary steam (to distinguish it from the steam inside the coil, usually called primary steam) is led into a condenser, and by the agency of cold