NAPHTHA-MOTORS. 



525 



waters. They are especially suited to the needs 

 of amateur engineers, from the small space occu- 

 pied by the machinery, the absence of smoke 

 and odor, and the ease with which they are 

 managed. While they can not compete with 

 the best coal and oil burning engines in actual 

 driving-power, they are efficient for most pur- 

 poses. Another advantage is that the engine 

 and attachments are so light that they can be 

 placed in the stern-sheets of the boat, leaving 

 the whole forward space available for passen- 

 gers, while the products of combustion are all 



NAPHTHA ENGINE. 



aft, and under most conditions of weather pass 

 off astern without the least annoyance to any 

 one on board. 



The naphtha used as fuel is stored in a tank 

 in the extreme bow, at the farthest possible re- 

 move from the fire, whence the only danger 

 arises, and the possibility of an explosion is 

 very remote. Indeed, the absenee of accidents 

 in the record shows that such a mishap is well- 

 nigh impossible. Deodorized naphtha of 76 is 

 used, its vapor supplying the cylinders in place 

 of steam, no water being required. An engine 

 of two-horse power weighs only 200 pounds, 

 and one of four-horse power weighs 300 

 pounds, less than one-fifth as much as a steam- 

 engine of the same power. The space occupied 

 is only eighteen inches fore and aft for the 

 smaller sizes, and but little more in proportion 

 as the power and size are increased. The 

 three single-action cylinders are contained in a 

 cast-iron casing, the upper part of which forms 

 the valve-seats, the cylinders being suspended 

 below and operated by plain valves connected 

 with one stem reaching from the crank-shaft. 

 On top of the casing is the boiler, consisting 

 of two coils of copper pipe, one within the 

 other, a vertical cylinder being set within the 



coils. The coils and cylinder are connected 

 with copper tubing, and the whole is included 

 in a brass casing, above which rises the smoke- 

 stack. The naphtha is carried by a pipe leading 

 from the reservoir in the bow, down through 

 the bottom of the boat, and aft outside the 

 keel to the inner coil of pipe, and thence down 

 and into the outer coil, from the top of which 

 it connects with the vertical cylinder. The 

 heavier gas passes directly to the engine, but 

 the.lighter is taken from the cylinder by a pipe 

 and carried to an injector, where it is mixed 

 with air and then delivered to the burner im- 

 mediately beneath the two coils, which are sur- 

 rounded with flame as soon as the burner is 

 lighted. That portion of the vapor which 

 passes from the engine is condensed in a tube 

 outside of the keel, and returns to the tank to 

 be used again, the only portion actually ex- 

 pended being that which is burned under the 

 coils. For a two-horse-power engine the con- 

 sumption is about three quarts an hour. There 

 is no possibility of flame reaching the tank ex- 

 cept through the long tube surrounded by 

 water and therefore constantly at a low tem- 

 perature. Herein lies the safety of the engine, 

 for it is nearly or quite impossible that any 

 circumstances can arise that will force a reverse 

 draught through such a long passage. The en- 

 gine is shown in detail herewith, exactly as it 

 appears resting upon the bottom of the boat. 

 A is an alcohol lamp, B is the air-valve, E the 

 air-pump, D naphtha- valve, F naphtha-pump, 

 C injector-valve, G governing-wheel, and H 

 safety-valve. To start the engine the alcohol 

 lamp A is lighted and set on the rest-plate, 

 with its tube inserted in the bottom of the re- 

 tort. The air-valve B is turned from left to 

 right, and with the air-pump E the gas is forced 

 from the tank through the outlet-pipe to the 

 burner, where it is ignited under the retort by 

 the flame of the lamp. The air-pump should 

 be used one or two minutes when the naphtha- 

 valve D may be opened. Five to ten strokes 

 on the pump F will bring the naphtha from the 

 tank to the already heated retort, where it is 

 at once vaporized, and the injector C is opened 

 slowly at first, supplying fuel to the burner, 

 after which the governor G is given a few 

 turns from right to left, until the machinery 

 begins to move. The pressure is increased by 

 a few strokes with the naphtha-pump F, and a 

 gauge shows the amount of pressure. This is 

 opened to increase and closed to reduce speed. 

 The lamp is removed and extinguished as soon 

 as the engine is running, and the pressure ia 

 regulated by the injector C so that it will re- 

 main stationary. 



The air-pump is used to force gas which has 

 generated in the tank through the pipe to the 

 burner, and is also used as a whistle by turn- 

 ing the air-valve B from right to left. The 

 tanks have from 30 to 60 gallons capacity. The 

 engine can be instantly reversed, even when 

 running at full speed, and headway is at once 

 checked and the boat brought to a full stop 



