This ash-pan door is not moved much, but the regulation of the air supply is by the valve control of the air and oil in the burner. The flame should be a steady, full, white or yellowish white one, filling the furnace.

The principal difficulties encountered were in the regulation of the supply of oil to the heaters by the pump, and the consequent variation of the temperature of the heated oil and the freedom of flow through the burners. An automatic submerged float, arranged like a steam trap and fitted in the oil heater to control the throttle of the failed to pump, give good automatic results, and the supply of oil was regulated by hand. If the oil is heated with too much (above 150°F.) some of the volatile gases are given off and mingle with the air pressing on top of the oil in the heater, thence passing with the air into the air superheaters, and burners, the result being that on one occasion a heater got red hot from this cause.

Another difficulty was due to the choking of the strainers by foreign matter and impurities in the oil, shutting off the supply of oil, and on one occasion, August 10, putting out all the fires. Just previous to the fires going out, and while the usual air supply was on, and an insufficient amount of oil being fed, a dense white smoke like steam arose from the funnel.

This strainer difficulty will be solved by fitting the strainers in pairs, so that a clean one can always be switched in while the choked one is being cleaned.

Generally the revolutions of the engines did not vary much during the day, and in calculating the horse-power for each day's average revolutions, when the cards for that day differed much, that set was selected whose revolutions were near the average for the day with the indicated horse-power, assumed to vary as the cube of the revolutions. If the two sets of cards for the day had the same number of revolutions their average indicated horse-power was used as a basis to compute the day's horse-power as before.

It will be noted that the log accompanying this report is kept from noon to noon. This was done as the patent log was inaccurate, and the speed of the ship was got from noon positions as given by sights.

It will be noted that speed was much higher on the return trip than on the outgoing, which is ascribed partly to the better combustion as the firemen got experience, partly to the overhauling of the bearings at Tahiti by the force on board, and mostly to the increased oil consumption allowed after the run down had proved that there was plenty of oil for the return trip, which was a matter of some doubt before, the ship being provided with coal for twenty-four hours to cover possible emergency.

Full power was not developed in the two boilers used, as schedule time was easily exceeded with from two to four burners shut off, though it would not appear, from the tabulated results, that the indicated horse-power would equal what can be got by a good system of forced draft. This burner, however, works well with the Howden system of forced draft, as seen on the tank steamer George Loomis.

It must be remembered that the tabulated calculations are all based on the indicated horse-power of the main engines only, as it was considered better to use only data actually obtained, and afterwards estimated data, such as indicated horse-power of auxiliaries, could be supplied without vitiating the observed data and results. No cards could be taken from any of the auxiliaries, but careful estimates give the following results

The

The

The size of air compressor was based on the assumption that it requires one cubic foot of free air for every pound of water evaporated from and at 212 ̊F., as shown by tests of various oil burners at Western Sugar Refinery, San Francisco.

The weights of oil auxiliaries are as follows—

It should be remembered that the boilers were designed for coal burning; that the oil-burning plant was fitted in a hurry, the machinists not leaving the ship until the gong rang for people to go ashore; that the firemen were without experience in oil burning, and that most of the automatic gear did not work properly.

With the air pressure constant; with the oil heated at constant temperature near 140°F.; with oil strainers arranged in pairs, so that one is always efficient, and with experience in firing, the results in economy of oil should be much better on the next trip; and the fireman's work, already very easy, will approach supervising automatic regulation. The fireman does not need strength nor previous training with coal. He should have a good eye, good ear, some common sense, and a desire to learn a new and easy trade. (Signed) WARD WINCHELL, Lieutenant, United States Navy.

CHIEF OF BUREAU OF STEAM ENGINEERING,

Navy Department, Washington, D.C.

Knots per day.

Knots per hour.

main

Oi! used per day

Oil used per day

(tons of 2,240

pounds).

Heating surface,

two double

ended boilers.

3,451 258 8.302

61-1 1,768 260

260 62.5 1,950

36-43 3,365

July 20 stopped 21
hours to plug leaky

tubes in condensers.

July 24

3,200

8.302

18-70

3.70

2,386

35.71

3,299 258

8,302

3.60

July 25

1-39 239 9.35

1.34

14.5

69-8

2,470 257

July 26

36-71 | 3,398

10-7

24

16

258

8,302

9.57

333

.72

13.9

69-1

2,129 258

36.86 3,432

258

8,302

8.25

.65

3.90

Total

set, trade wind port
beam.

3,438

2,803 400-43

Average

13.12 65-2

2,193 254-8

260 31

Average

made

round trip.

speed 325-7

during

NOTE.-The Bureau has also received the following summary of the second voyage of the steamship Mariposa on the round trip between San Francisco and Tahiti. These data show that the oil consumption on the second voyage was considerably less than that on the first, due to two causes: Improvements in detail of the oil-fuel installation, and increased skill and intelligence upon the part of the engine-room force.

The Occidental Steamship Company is fitting an oil-fuel installation on the sister ship Alameda, and it can be expected that when a spirited rivalry is created between the crews of the Alameda and Mariposa, even better results can be anticipated.

O.S.S." Mariposa," voyage No. 2, from San Francisco to Tahiti, 1902.

Voyage 1, 11 days

Average temperature of uptake, 548°; average temperature of superheaters, 360°; average temperature of cold oil, 91°.

O.S.S. "Mariposa," voyage No. 2, from Tahiti to San Francisco, 1902.

Average temperature of uptake, 546°; average temperature of superheaters, 360°; average temperature

of cold oil, 90°.

Appendix No. 3

EXTRACT FROM REPORT OF BOARD ON TESTS OF LIQUID FUEL FOR

NAVAL PURPOSES.

DEPARTMENT OF THE NAVY,

BUREAU OF STEAM ENGINEERING,

WASHINGTON, D.C., October 1, 1902.

SIR, -The board appointed to conduct an extended series of tests to determine the value of liquid fuel for naval purposes submits the following preliminary reportThe board is of the opinion that the best interests of the Navy will be subserved by making public at this time the data and information collected during the fourteen official experiments that have been conducted.

reliable.

Upon investigation the board finds that much of the data published is very particularly upon the most important features of the problem. As an illustration, it has been asserted that the boilers of some merchant vessels only consume, for sustained sea work, 1 pound of oil to develop 1 horse-power. When it comes to checking this information by the consumption from the storage tanks it will be found that a much larger quantity is used.

It is directly within the sphere of the Navy Department to conduct an extended series of experiments that will be of great value to the shipbuilding and manufacturing interests, even if the Navy does not receive an immediate return.

The naval problem is a quite complicated one, and an extended series of experiments to determine the value of liquid fuel for ships of war should be conducted for at least a year. The board recognizes the fact that the commercial phase of the liquid-fuel question as regards the Navy is quite different from what it is in the merchant marine, and that it will be much more difficult to ensure an adequate supply for ships of war than for merchant vessels. It will also tax the ability of the naval constructor to solve the construction problem involved in installing oil-fuel appliances on board the battle ship, since it will not be possible to find such satisfactory storage compartments in the fighting ship as in the freighter.

Engineering Features of the Oil-Fuel Problem.

It is the engineering or mechanical feature of the problem that the board is concentrating its energies upon. Therefore the board proposes to try to solve some of the following problems in connexion with the subject

1. The relative advantages of air and steam as an atomizing agent for liquid fuel. The question of supply of fresh water is very important in the Navy, and therefore the use of steam should be obviated, if possible. On the other hand, the air compressors are quite heavy and take up considerable room. As air compressors, however, are used for many purposes on board ship, it might be possible to have a central plant for all purposes. It is also important to know to what extent it will be necessary to superheat the steam in case it is used as the atomizing agent.