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216 cated horsepower, 1.5 gallons per day of cylinder oil were used at first for internal lubricating and swabbing of piston-rods of both main and auxiliary engines; on the Port Lincoln and Port Macquarie, of 4,000. indicated horsepower, about 2 gallons per day, this being gradually reduced until now only 0.5 to 0.75 gallon is required. An- other important detail with regard to this is that independent means of lu- brication must be provided for each engine, either in the valve-chest or cylinder. That for the high-pressure cylinder should be on the engine side of the stop and throttle-valve, other- wise the surfaces are liable to become coated with an oil deposit during a long run, and may cause them to work stiff, thereby interfering with their steam tightness when brought into use again on working the engines to orders. It is advisable to arrange for independent lubrication for the low- pressure valve, as owing to its being generally of the flat "D" type and unbalanced, the large surface even with a low pressure upon it, gives rise to considerable friction. It has been found in triple expansion en- gines, where the medium-pressure cyl- inder is placed adjoining the high- pressure cylinder with shost exhaust passages, that, after the surfaces be- come saturated with oil, the regular supply to the medium-pressure cylin- der may be shut off, as it would ap- pear that a sufficient quantity of the oil injected into the steam in the high- pressure valve chest becomes vapor- ized and is carried over to the me- dium-pressure valve chest with the ex- haust. Nevertheless, in the first in- stance, a regular supply should be in- jected into the medium-pressure valve chest, and even when this is shut off, a little extra oil should be: injected from time to time, according to the evidence of the running and condi- tion of the surface when opened up for examination. Problem of Lubrication The selection of a suitable lubricant for internal lubrication under the tem- peratures and conditions met with when using superheated steam is one requiring consideration. several oils on the market with a flash-point under the from 610 deg. to 630 deg. Fahr., but due consideration must be given to their composition, whether it repre- sents an absolute mineral oil, or a compound of a mineral with an ani- mal or vegetable oil, which, it is claimed, adds to the lubricating quali- ties without creating troubles from catbonization or other causes; this, There are: open test of THE MARINE REVIEW however, is a doubtful point. Upon the question of the evaporation-point, and also the flash-point, when the oil is under pressure, we know of no, re- liable data; possibly these points are higher under pressure than those obr tained by the tests under atmospheric conditions. It is absolutely necessary to have a reliable system of filtration for the feed-water, so as to ensure the abstraction of the oil and to safe- guard the boilers from the possibility of any traces getting through. The difficulties at first met with to obtain this result have been overcome by fitting a large gravitation filter. Filtration The whole secret of filtration is "time" to allow the feed-water to come almost to rest, and enable the oil to rise to the surface and be col- lected; afterwards the feed-water should pass through a chamber filled with coke, and finally through a sec- tion fitted with "cartridge" cylinders, covered with filter-cloth toweling of substantial body having a rough sur- face. The more compartments of the first or settling stage that are pro- vided, the longer the coke and filter- cloth sections will last without requir- ing to be changed. The filter must June, 1914 The feed-water betrays not the slight- est sign of oil, even in emulsion, when drawn off from the feed-pumps; there is no "taste" of oil perceptible; the internal surfaces of the boilers, even on the water-liné do not show any signs of oil, and this has been con- firmed in each of the four boilers in both the steamers with quadruple ex- pansion engines having passenger cer- tificates, upon inspection at the end of six and twelve months' service, as °: well as at the annual survey on the other steamer, fitted with triple ex- pansion engines and two boilers. The temperature of the steam during the various stages is ascertained by py- rometers fitted to the superheater steam pipe of each ~' boiler "to the MH Pe oand "MOR 2 gteam chests, and by thermometers fitted in the steam chests of the M. P. 2 and L. P. engines. The general experience with the pyrometers havy- ing long connecting capillary tubes filled with ether or mercury, by means of which the temperature is recorded on the dial, shows a tendency to give unduly low readings after months of constant use, to the extent of about 5 per cent, necessitating their being fre- quently tested, and short connections S. S. Port Augusta. Triple Expansion Engines. S. S. Port Lincoln and Port Macquarie. Quadruple Expansion Engines. Temper- Temper- = Gage ature Tempera- Degree Gage ature Tempera- Degree pressure due to ture of - pressure due to ture of insteam steam recorded, superheat,insteam steam recorded, superheat, chests, pressure, deg. deg. chests, pressure, deg. deg. Steam Chest. lb: deg. Fahr. Fahr. Fahr. lb. deg. Fahr. Fahr. Fahr. High pressure ..... 160 370 550 180 206 389 600 +211 First intermediate .. 53 300 400 100 97 335 460 +125 Second intermediate. 38 284 290 + 6 ow. > pressure...<.<.... 10 240 ? ? 9 237 220 -- 17 be so placed that the water will gravi- tate to the same water-level as the weir in the hot-well of the air pumps. It is essential that the covers of this filter should be always open when working, so that it may be under ob- servation, and that the thick scum ac- cumulating on the surface of the set- tling chambers may be removed by hand from time to time. The cleaning of the coke and filter- cloth chambers can be done very quickly if a full set of spare parts is carried, which can be kept charged with fresh coke and with clean filter- cloths on, ready for use. When such spare parts are provided there is no necessity for a by-pass arrangement, as the working of the filter is not in- terfered with during the process of changing the filtering medium, and the time is so short that no danger from oil passing through with the feed-water is experienced. are therefore recommended, although the position of the dials may not then be so conveniently arranged for ob- servation. The variations in the read- ing of the pyrometers, due to the fluctuations of the temperature of the steam following on the condition of the fires, indicate beforehand the rise or fall of the steam pressure, and enable the engineer on watch to know in which boiler the furnace tempera- tures are falling, through the fires getting low or dirty, and so give the necessary orders to maintain a full steam pressure. The fitting of py- rometers and thermometers in_ this manner has given some very inter- esting information as to how far the superheat is carried through the en- gine, in other words, whether the tem- perature of the steam due to super- heat falls more or less quickly than the temperature of the steam conse- quent upon the pressure, so as to in-