STEAM NAVIGATION. 



397 



of lime is made. These, with other ingredients 

 form so hard an incrustation on the inner surface 

 of the hoilers, particularly in the cavities about the 

 furnaces and flues, as to render the generation of a 

 sufficient quantity of steam a matter of considerable 

 difficulty on long voyages. As this crust continues 

 to thicken the heat is impeded by it, and the metal 

 of the boilers becomes overheated, raising it to a 

 temperature much above that of the water, and in 

 some instances to such an extent that the boilers 

 become red hot and burn. The consequence is a 

 rapid destruction of the boiler, an unnecessary waste 

 of fuel, and great labour in removing the crust at 

 the termination of each voyage. 



Engineers have suggested a variety of methods 

 for carrying off the salt ; among others a process of 

 discharging several tons of water from the boilers 

 every twenty-four hours, or oftener, and termed 

 blowing out. But the most effectual remedy yet 

 suggested for the removing of this obstacle, appears 

 to be that of Mr S. Hall, of Basford, near Notting- 

 ham, who has become patentee for a new form of 

 condenser, specially intended for preventing the ac- 

 cumulation of salt in marine boilers, &c. 



Mr Hall's condenser consists of a cast iron cistern, 

 situated where the common condenser is usually 

 placed in other engines. At the top and bottom of 

 this cistern a flat chamber is formed by two brass 

 plates which are accurately fitted into the cistern, 

 and made steam tight. These two plates are closely 

 perforated, into which perforations the extremities 

 of as many composition tubes are introduced, and 

 made tight by a peculiar method of stuffing, to allow 

 of their expansion without permitting the steam to 

 escape through the stuffing boxes or any injury to 

 the tubes. 



From the cylinder the steam escapes to the upper 

 chamber of the condenser and then descends verti- 

 cally through the tubes to the lower chamber, into 

 which it enters in the form of pure water (being 

 condensed by the cold surfaces of the tubes in its 

 descent) in which form, it is thence dravvn off by 

 the air pump and again conveyed into the boilers. 

 While the steam is thus continuously passing 

 through the inside of the tubes, a regular stream of 

 cold sea water is injected by a force pump into the 

 cistern, and made circulate among them, which, cool- 

 ing their external surfaces, causes a condensation of 

 the steam. This water is again forced into the sea 

 and replaced by a fresh supply from the force pump. 

 It is indeed a regular current of cold water flowing 

 incessantly through among the tubes. 



From the above description, it is evident that no 

 waste of the water originally introduced into the 

 boilers will take place, but what arises from leak- 

 age ; so if the boilers be filled with pure water, it 

 may be worked for any length of time without in- 

 jury. The small quantity lost by leakage is sup- 

 plied by a small apparatus, in which a sufficient 

 quantity of sea water is distilled. 



The steam, which in other engines is allowed to 

 escape through the safety valve into the atmosphere 

 when the vessel stops, or when the engines are 

 working at an under power, is in Mr Hall's engines 

 conveyed by a safety valve of a peculiar construc- 

 tion, communicating with a tube to the condenser. 

 It is then reconverted into water and pumped into 

 the boilers by the air pump. 



The following are the advantages, as stated by 

 Mr Hall, to be gained by his condenser : 1. A 

 saving of fuel, amounting, in some cases, to so much 

 as a third of the ordinary consumption. 2. The 



preservation of the boilers from the destruction 

 produced in common engines by the corrosive ac- 

 tion of sea or other impure water, and by incrusta- 

 tions of earthy matter. 3. The saving of the time 

 spent in cleaning the boiler. 4. A considerable in- 

 crease of power, owing to the cleanness of the 

 boilers ; the absence of injected water to be pumped 

 out of a vacuum ; the greater perfection of the 

 vacuum ; the better preservation of the piston and 

 valves of the air pump ; and (by another contriv- 

 ance of his) the more perfect lubrication of the 

 parts of the engine. 5. The water in the boiler 

 being constantly maintained at the same height by 

 self-acting arrangement. 6. The size of a boiler 

 exerting a given power, being much smaller than 

 the common kind, owing to its more perfect ac- 

 tion. 



P. Borrie having obtained a licence from the 

 patentee for making this condenser, has, at the re- 

 quest of the Company to whom the Sea Horse be- 

 longs, fitted her engines up with two of them. 



The number of tubes in the condenser shown is 

 2621 ; inch diameter, and five feet eight inches 

 long, metal No. 21, W. G. thickness. These tubes 

 are made of a composition of copper and tin, and are 

 all well tested before being used. 



As is shown in the transverse section, fig. 6, the 

 Sea-horse has two engines of 120 horse power, each 

 having cylinders fifty-five inches diameter, with a 

 stroke of five feet, and makes twenty-one strokes 

 per minute. The paddle wheels are twenty-one 

 feet diameter and 8 feet broad, and their circum- 

 ference gives a velocity of 15 miles an hour. 



This vessel is also provided with two powerful 

 double-acting force-pumps, used for filling the boilers 

 with water or pumping out the bilge water when 

 necessary. A hose is provided, and at a moment's 

 notice can be attached to them ; so that in case of 

 fire on board, a continuous and powerful stream of 

 water can be instantly conveyed to any part of the 

 vessel, and answer, on such an occasion, all the pur- 

 poses of a fire engine. 



The saloon of the after cabin occupies a space of 

 650 square feet, being forty feet in length and eight 

 feet high. In connection with the saloon are two 

 state rooms, one gentlemen's and one ladies' cabin, 

 also an ample lobby and steward's pantry and other 

 necessary conveniences, as will be indicated by the 

 references on the plate. The sofas are all so con- 

 structed that, when required, they are available as 

 sleeping berths, making in all, with the matress beds, 

 fifty-four berths in the after cabin; besides the move- 

 able sofa berths, which will accommodate eight or 

 ten more. 



The saloon table will accommodate fifty at din- 

 ner. The panneling of the saloon is embellished 

 with landscape and sea views, and otherwise superb- 

 ly decorated, that may justly entitle it to the de- 

 signation of a floating palace. 



The fore cabin is also spacious, being eight feet 

 high, and fitted up in a very elegant manner. Be- 

 sides the main fore cabin, in area 240 square feet, 

 there is a commodious cabin for the ladies, contain- 

 ing eighteen sleeping berths and other conveniences. 

 The main cabin has sleeping berths for thirty ; in all 

 forty-eight sleeping berths in fore cabin. The 

 dining table of this cabin can accommodate forty- 

 three persons. 



On deck, fore and aft the paddle boxes, on each 

 side, are the cook's pantry> cooking apparatus, wa- 

 ter closets, &c., and in the engine room and fore- 

 castle are sleeping berths for engineers and crew. 



