Chapter 3

_Driving locomotives._--In lighting up, certain precise rules have to be followed, in order to prevent explosion of any gas that may have accumulated in the fire box. Such explosions do often take place through negligence; but they amount simply to a puff of gas, driving smoke out through the ash-pan dampers, without any disagreeably loud report. This is all prevented by adhering to the following simple rules: First clear the spray nozzle of water by letting a small quantity of steam blow through, with the ash-pan doors open; at the same time start the blower in the chimney for a few seconds, and the gas, if any, will be immediately drawn up the chimney. Next place on the bottom of the combustion chamber a piece of cotton waste, or a handful of shavings saturated with petroleum and burning with a flame. Then by opening first the steam valve of the spray injector, and next the petroleum valve gently, the very first spray of oil coming on the flaming waste immediately ignites without any explosion whatever; after which the quantity of fuel can be increased at pleasure. By looking at the top of the chimney, the supply of petroleum can be regulated by observing the smoke. The general rule is to allow a transparent light smoke to escape, thus showing that neither too much air is being admitted nor too little. The combustion is quite under the control of the driver, and the regulation can be so effected as to prevent smoke altogether. While running, it is indispensable that the driver and fireman should act together, the latter having at his side of the engine the four handles for regulating the fire, namely, the steam wheel and the petroleum wheel for the spray injector, and the two ash-pan door handles in which there are notches for regulating the air admission. Each alteration in the position of the reversing lever or screw, as well as in the degree of opening of the steam regulator or the blast pipe, requires a corresponding alteration of the fire. Generally the driver generally passes the word when he intends shutting off steam, so that the alteration in the firing can be effected before the steam is actually shut off; and in this way the regulation of the fire and that of the steam are virtually done together. All this care is necessary to prevent smoke, which is nothing less than a waste of fuel. When, for instance, the train arrives at the top of a bank, which it has to go down with the brakes on, exactly at the moment of the driver shutting off the steam and shifting the reversing lever into full forward gear, the petroleum and steam are shut off from the spray injector, the ash-pan doors are closed, and if the incline be a long one, the revolving iron damper over the chimney top is moved into position, closing the chimney, though not hermetically. The accumulated heat is thereby retained in the fire-box; and the steam even rises in pressure, from the action of the accumulated heat alone. As 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 18-1/8 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. 2-3/4 in.; between middle and trailing, 4 ft. 9-1/4 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, 2-1/8 in.; length between tube plates, 13 ft. 10-1/8 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.

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

+---+-----+------+---+-----+------+-----------+-------------+------+------------ | L | | | | | | | | | o | | Train | | | | Consumption | | | c | | alone. | | | | Including | | Date.| o | | | | | | Lighting up.| | 1883.| m | |----+-----| | | | | Cost | | o |Train|Num-| | Dis-| Car | | | of |Atmospheric | t | |ber |Gross|tance|miles.| Fuel. |-------+-----| fuel |temperature | i | | of |load.| run.| | | | Per | per | and | v | |Loa-| | | | | Total |train| train| weather. | e | |ded | | | | | |mile.| mile.| | . | |cars| | | | | | | | -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------ | | | No.| Tons|Miles| | | | |Pence.| -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------ | 8|32-23| 25 | 400 | 388 | 9,700|Anthracite.| 31799 |81.90|11.957|-17° to -18° | |32-23| | | | | | lb. | lb. | | Reau., Feb.| | | | | | | | | | | equiv. to 8 | |24-21| | | | | | | | |-6° to -8½° | 14|24-21| 25 | 400 | 388 | 9,700|Bituminous |37557.5|96.53|14.093| Fah. | | | | | | | Coal. | lb. | lb. | | | 7|26-29| 25 | 400 | 194 | 4,830|Petroleum | 9462 |48.77| 5.487| Strong | | | | | | refuse. | lb. | lb. | | side wind. -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------ | 24|32-23| 25 | 400 | 194 | 4,850|Anthracite.|12639.5|65.15| 9.512|-5° to -9° March| | | | | | | | lb. | lb. | | Reau., 6 | 21|24-21| 25 | 400 | 194 | 4,850|Wood, in | 1071.8| 5.52| 8.5 | equiv. to | | | | | | | billets. | c. ft.|c. ft| | 21° to 12° | | | | | | | | | Fah. | 23|26-27| 25 | 400 | 194 | 4,850|Petroleum | 7228 |37.28| 4.188| Light | | | | | | refuse. | lb. | lb. | | side wind. -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------

Prices of fuel: Petroleum refuse, 21s. per ton; Anthracite and bituminous coal, 27s. 3d. per ton; Wood, in billets, 42s. per cubic sajene = 343 cubic feet; equivalent to 1.47d. per cubic foot.

Dimensions of locomotives: Cylinders, 18 1/8 in. diam. and 24 in. stroke; Wheels, 4 feet 3 in. diam.; Total heating surface, 1,248 sq. feet: Total adhesion weight, 36 tons; Boiler pressure, 8 to 9 atm.

The preceding table shows the results of comparative trials made in winter with different sorts of fuel, under exactly similar conditions as to type of engine, profile of line, and load of train. Two sets of comparative trials were made, both of them in winter. The three engines used were some of those built by Schneider. In comparison with anthracite, the economy in favor of petroleum refuse was 41 per cent. in weight, and 55 per cent. in cost. With bituminous coal there was a difference of 49 per cent. in favor of petroleum as to weight and 61 per cent. as to cost. As compared with wood petroleum was 50 per cent. cheaper. At a speed of fourteen miles an hour up an incline of 1 in 125 the steam pressure was easily kept up at 9 to 9½ atm. with a No. 9 injector feeding the boiler all the time.

Up to the present time the author has altered seventy-two locomotives to burn petroleum; and from his own personal observations made on the foot plate with considerable frost he is satisfied that no other fuel can compare with petroleum either for locomotives or for other purposes. In illustration of its safety in case of accident, a photograph was exhibited of an accident that occurred on the author's line on 30th December, 1883, when a locomotive fired with petroleum ran down the side of an embankment, taking the train after it; no explosion or conflagration of any kind took place under such trying circumstances, thus affording some proof of the safety of the petroleum refuse in this mode of firing. Although it is scarcely possible that petroleum firing will ever be of use for locomotives on the ordinary railways of coal-bearing England, yet the author is convinced chat, even in such a country, its employment would be an enormous boon on underground lines.

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CHARCOAL KILNS.

In answer to the inquiry of a correspondent about charcoal making, we offer two illustrations that show a method of manufacture differing from that usually adopted, which is that of burning on the bare ground, and covering with soil or sods to exclude the air. These kilns are made of brick, one course being sufficient, bands of iron or timber framework being added to strengthen the brickwork with greater economy. The usual style is conical, and the size is 24 feet in diameter, with an equal height, holding about 40 cords of wood. The difference in price is 1-1/8 d. per bushel in favor of these kilns as compared with the usual mounds, the burner being furnished with the use of the kilns, and the timber standing, the kiln burning costing 2-1/8 d., and the other 3-1/4 d. The kilns must be lined to about halfway up with fire-brick, the cost of which will vary with the locality, but will be about £200, and as 40 to 50 bushels of coal have been made per cord the extra yield on good charcoal and the lessening of the cost of making soon covers any extra outlay on the cost of the kilns. The wall of the kiln is carried up nearly straight for 6 feet, when it is drawn in, so as to become bluntly conical. Upon the top a plate of iron is fastened in the manner of the keystone of an arch, and bands of iron are passed round the kiln and drawn tight with screw bolts and nuts to strengthen it. Double doors of sheet-iron are made at the bottom and near the tops, by which it is either filled or emptied, and a few air-holes (B), which may be stopped with loose bricks, left in the bottom. The second figure shows a kiln of another shape made to burn 3,000 bushels of charcoal, or about 80 cords of wood. The shape is a parallelogram, having an arched roof, and it is strengthened by a framework of timber 10 inches square. As the pressure of the gas is sometimes very great, the walls must be built a brick and a half thick to prevent their bursting. The usual size is 16 feet wide and high, and 40 feet in length, outside measure. The time occupied in filling, burning, and emptying a small cone is about three weeks, and four weeks is required for the larger ones.--_The Gardeners' Chronicle._

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ENTRANCE, TIDDINGTON HOUSE, OXON.

Our illustration is a view of the entrance facade to Tiddington House, Oxfordshire, the residence of the Rev. Joshua Bennett. The house is an old building of the Georgian period, and though originally plain and unpretentious, its bold coved cornices under the eaves, its rubbed and shaped arches, moulded strings, and thick sash bars, made it of considerable interest to the admirers of the "Queen Anne" school of architecture, and led to the adoption of that style in the alterations and additions made last year, of which the work shown in our illustration formed a small part. Between the "entrance facade" and the wall of the house there is a space of some twenty feet in length, which is inclosed by a substantially built conservatory-like erection of Queen Anne design, forming an outer hall.

The works were executed by Messrs. Holly & Butler, of Nettlebed. The brick carving was beautifully done by the late Mr. Finlay; and the architects were Messrs. Morris & Stallwood, of Reading.--_The Architect._

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NEW ARRANGEMENT OF THE BICHROMATE OF POTASH PILE.

Since Poggendorff in 1842 thought of substituting in the Bunsen battery a solution of bichromate of potash and sulphuric acid for nitric acid, and of thus making a single liquid pile of it, in suppressing the porous vessel, his idea has been taken up a considerable number of times. Some rediscovered it simply, while others, who were better posted in regard to the work of their predecessors, took Poggendorff's pile as he conceived it, and, considering the future that was in store for it, thought only of modifying it in order to render it better. Among these, Mr. Grenet was one of the first to present the bichromate of potash pile under a truly practical form. As long ago as 1856, in fact, he gave it the form that is still in use, and that is known as the bottle pile. Thus constructed, this pile, as is well known, presents a feeble internal resistance, and a greater electro-motive power than the Bunsen element. Unfortunately, its energy rapidly decreases, and the alteration of the liquid, as well as the large deposit of oxide of chromium that occurs on the positive electrode, prevents its being employed in experiments of quite long duration. Mr. Grenet, it is true, obviated these two defects by first renewing the liquid slowly and continuously, and causing a current of air to bubble up in the pile so as to detach the oxide of chromium in measure as the deposit formed. Thus improved, the bichromate pile was employed on a large scale in the lighting of the Comptoir d'Escompte. In an extensive application like this latter, the use of compressed air for renewing the liquid can be easily adapted to the bichromate pile, as the number of elements is great enough to allow of the putting in of all the piping necessary; but when it is only desired to use this pile for laboratory purposes, and when there is need of but a small number of elements, it is impossible to adopt Mr. Grenet's elements in the form required by an electric lighting installation. It becomes absolutely necessary, then, to come back to a simpler form, and attempt at the same time to obviate the defects which are inherent to its very principle. In accordance with this idea, it will be well to point out the arrangement adopted by Mr. Courtot for his bichromate of potash piles--an arrangement that is very simple, but, sufficiently well worked out to render the use of it convenient in a laboratory.

Fig. 1 gives the most elementary form. It consists of an earthen vessel into which dip four carbon plates connected with each other by a copper ring which carries one of the terminals. In the center there is a cylindrical porous vessel that contains a very dilute and feebly acidulated solution of bichromate of potash into which dips a prism of zinc, which may be lifted by means of a rod when the pile ceases to operate. It is true that the presence of the porous vessel in the bichromate of potash element increases the internal resistance, but, as an offset, although it decreases the discharge, it secures constancy and quite a long duration for it.

The elements thus constituted may be grouped, to the number of six, in a frame analogous to that shown in the engraving, and, sum total, form a small sized battery adapted to the current experiments of the laboratory, and capable of supplying two small four volt lamps for ten or twelve hours. We have had occasion to make use of these elements for the graduation of galvanometers, and, after ascertaining the constancy of the discharge, have found that the internal resistance of each couple is nearly 0.175 ohm, with an electro-motive force of two volts. As may be seen, these elements should, in general, all be mounted for tension, as they are in the figure, inasmuch as the mobility of the zincs permits, according to circumstances, of employing a variable number of them without changing anything. Moreover, with zincs amalgamated in a special manner, the attack is imperceptible, and the work in open circuit need scarcely to be taken into consideration.

Yet, despite the qualities inherent to the arrangement that we have just described, that defect common to all bichromate of potash piles--the deposit of oxide of chromium upon the carbon--is not here avoided. It occurs quite slowly, to be sure, but it does occur, and, from this point of view, the arrangement shown in Fig. 2 is preferable. The elements here are composed of prismatic porcelain vessels containing, as before, the solution and porous vessel.

The whole is covered with a sheet of ebonite connected with the zinc and the two carbon plates in such a way that when the pile is not in operation the whole can be lifted from the liquid. Under such circumstances the deposit of oxide is notably diminished, and the duration of the discharge is consequently greatly increased.

Fig. 3 shows the details of a windlass that permits of lifting, according to circumstances, all the elements of the same trough or only a part of them. To effect this, the drum around which the chain winds that carries the carbons is mounted upon a sleeve fixed upon the axle. This latter is actuated by a winch; and a ratchet wheel, R, joined to a click which is actuated by a spiral spring, prevents the ebonite plates from falling back when it is desired to place the bolt under the button, B, of the spring.