soon as the train reaches the bottom of the incline and steam is again required, the first thing done is to uncover the chimney top; then the steam is turned on to the spray injector, and next a small quantity of petroleum is admitted, but without opening the ash-pan doors, a small fire being rendered possible by the entrance of air around the spray injector, as well as by possible leakage past the ash-pan doors. The spray immediately coming in contact with the hot chamber ignites without any audible explosion; and the ash-pan doors are finally opened, when considerable power is required, or when the air otherwise admitted is not sufficient to support complete combustion. By looking at the fire through the sight hole it can always be seen at night whether the fire is white or dusky; in fact, with altogether inexperienced men it was found that after a few trips they could become quite expert in firing with petroleum. The better men contrive to burn less fuel than others, simply by greater care in attending to all the points essential to success. At present seventy-two locomotives are running with petroleum firing; ten of them are passenger engines, seventeen are eight-wheel coupled goods engines, and forty-five are six-wheel coupled. As might be expected, several points have arisen which must be dealt with in order to insure success. For instance, the distance ring between the plates around the firing door is apt to leak, in consequence of the intense heat driven against it, and the absence of water circulation; it is therefore either protected by having the brick arch built up against it, or, better still, it is taken out altogether when the engines are in for repairs, and a flange joint is substituted, similar to what is now used in the engines of the London and Northwestern Railway. This arrangement gives better results, and occasions no trouble whatever.

Storage of petroleum.—The length of line now worked with petroleum is from Tsaritsin to Burnack, 291 miles. There is a main iron reservoir for petroleum at each of the four engine sheds, namely at Tsaritsin, Archeda, Filonoff, and Borisoglebsk. Each reservoir is 66 ft. internal diameter and 24 ft. high, and when full holds about 2,050 tons. The method of charging the reservoir, which stands a good way from the line, and is situated at a convenient distance from all dwelling houses and buildings, is as follows: On a siding specially prepared for the purpose are placed ten cistern cars full of oil, the capacity of each being about ten tons. From each of these cars a connection is made by a flexible India rubber pipe to one of ten stand pipes which project 1 ft. above the ground line. Parallel with the rails is laid a main pipe, with which the ten stand pipes are all connected, thus forming one general suction main. About the middle of the length of the main, which is laid underground and covered with sawdust or other non-conducting material, is fixed a Blake steam pump. As soon as all the ten connections are made with the cistern cars, the pump is set to work, and in about one hour the whole of the cars are discharged into the main reservoir, the time depending of course upon the capacity of the pump. All the pipes used are of malleable iron, lap-welded, and of 5 in. internal diameter, having screwed coupling muffs for making the connections. At each engine shed, in addition to the main storage reservoir, there is a smaller distributing tank, which is erected at a sufficient height to supply the tenders, and very much resembles the ordinary water tanks. These distributing tanks are circular, about 8½ ft. diameter and 6 ft. high, and of ¼ in. plates; their inside mean area is calculated exactly, and a scale graduated in inches stands in the middle of the tank; a glass with scale is used outside in summer time. Each inch in height on the scale is converted into cubic feet, and then by means of a table is converted into Russian poods, according to the specific gravity at various temperatures. As it would be superfluous to graduate the table for each separate degree of temperature, the columns in the table show the weights for every 8 degrees Reaumur, which is quite sufficient: namely, from 24 deg. to 17 deg., from 16 deg. to 9 deg., and so on, down to -24 deg.; the equivalent Fahrenheit range being from 86 deg. down to -22 deg. Suppose the filling of a tender tank draws off a height of 27 in. from the distributing tank, at a temperature of say -20 deg. R., these figures are shown by the table to correspond with 200.61 poods = 7,245 lb., or 3.23 tons, of petroleum. This arrangement does very well in practice; both the quantity and the temperature are entered on the driver's fuel bill at the time of his taking in his supply.

Engines.—The engines used in the trials were built by Borsig, of Berlin, Schneider, of Creusot, and the Russian Mechanical and Mining Company, of St. Petersburg. Their main dimensions and weights were about the same, as follows, all of them having six wheels coupled, and 36 tons adhesive weight; as originally constructed they had ordinary fire boxes for burning anthracite or wood; cylinders 18⅛ in. diameter and 24 in. stroke; slide valves, outside lap 1-1/16 in., inside lap 3/32 in., maximum travel, 4-9/16 in.; Stephenson link motion; boiler pressure, 120 lb. per square inch; six wheels, all coupled, 4 ft. 3 in. in diameter; distance between centers of leading and middle wheels, 6 ft. 2¾ in.; between middle and trailing, 4 ft. 9¼ in.; total length of wheel base, 11 ft.; weight empty, on leading wheels, 12.041 tons; middle, 10.782 tons; trailing, 10.685 tons; total weight, 33.508 tons empty; weight in running order, on leading wheels, 12.563 tons; middle, 11.885 tons; trailing 12.790 tons; total weight, 37.238 tons in running order. Tubes number 151; outside diameter, 2⅛ in.; length between tube plates, 13 ft. 10⅛ in.; outside heating surface, 1,166 square feet; fire box heating surface, 82 square feet; total heating surface, 1,248 square feet; fire grate area, 17 square feet;tractive power = 65 per cent. of boiler pressure × (cyl. diam.)² × stroke / diameter of wheels = 0.65 × 120 × (18.125)² × 24 / 51 = 5.383 tons. Ratio of tractive power to adhesion weight = 5.383 / 37.238 = 1 / 6.9.

Tender.—Contents: water, 310 cubic feet, or 1,933 gallons, or 8½ tons; anthracite, 600 poods, or 10 tons; or wood, 1½ cubic sajene, or 514 cubic feet; weight empty, 13.477 tons; weight in running order, 28.665 tons; six wheels.

Petroleum Refuse—Comparative Trials with Petroleum, Anthracite, Bituminous Coal, and Wood, between Archeda and Tsaritsin on Grazi and Tsaritsin Railway, in Winter Time.