March 15, 1918. THE COLLIERY GUARDIAN 539 with the result that the man at the 150 fm. level would signal to release the cage or skip immediately, so that the engineman could attend to the needs of the more urgent case, which, of course, he could not do until receiving the release signal from the 150 fm. level. The following code of signals is used at East Pool for distinguishing the different levels :— No. 1 Level, 1—1; No. 2, 1—2; No. 3, 1—3; No. 4, 1— 4; No. 5, 1—5 ; No. 6, 2—1; No. 7, 2—2; No. 8, 2— 3; No. 9, 2—4 ; No. 10, 2—5 , No. 11, 3—1; No. 12. 3— 2; No. 13, 3—3; No. 14, 3-4; No. 15, 3—5; No. 16, 4— 2; No. 17, 4—3; No. 18, 4—4; No. 19, 4—5; No. 20, 5— 1; No. 21,5—2; No. 22, 5—3; No. 23,5—4; No. 24, 5—5. “ Cage wanted,” ... 6, and distinctive number of level. Men getting on ”—cage not to be moved without further signal ... 4. ‘‘ Men, or ore, from level to surface direct” ... 1. “ When in motion, to stop immediately ”... 1. THE AMERICAN COAL TRADE. Warmer weather has lessened the demand for house- hold fuel, and the freight situation shows signs of improvement. The Fuel Controller states that there will be no necessity for the shutting down of industry in the future, as he believes it possible henceforth to rely upon embargoes and the preference in the move- ment of food and fuel. The Coal Age (Feb. 16) reports that operators in Washington are in the air as regards the policy of the Fuel Administration. If that body would come out with a definite statement of its attitude on contracts, its feeling towards jobbers, and its intentions regarding prices, it would go far toward clearing up a great deal of uncertainty. Many operators are marking time in so far as the purchases of machinery and equipment are concerned, for they have no means of knowing if the new price schedule would justify any considerable investment in extensions to plant. The New England situation appears to be worse, but loading at Hampton Roads is rather better. Anthracite is extremely scarce in that direction. A British collier arrived there with Welsh coal for British warships. The amount of bituminous coal consigned from the Philadelphia region on strictly commercial orders remains at a low ebb, and even when consignments are made on such orders the chances are much against their ever reaching the original consignee, owing to the many chances of confiscation encountered en route. Many plants in this territory continue to be idle for lack of fuel. Baltimore reports a shortage of bituminous, and open market transactions in Pittsburg are non-existent. By an arrangement with the dealers who have been handling anthracite buckwheat for their steam trade, the bituminous coal is being used to replace buckwheat and this latter size turned over to domestic users. Often also a mixture of both is sold to the family trade. The com- plaint as to poor preparation of anthracite coal has now culminated in an investigation being started by the fuel authorities. It is understood that some action is on foot to change the entire system of distribution of coal beginning with April 1. The prices quoted in Philadelphia per gross ton f.o.b. cars at mines for line shipments are as follow :— Dois. Dois. Broken........... 5’9" | Buck ........ 3’15 Egg ............. 4'80 Rice .......... 2’65 Stove ........... 5'05 Boiler ........ 2'45 Nut ............. 5'15 Barley ....... 2'15 Pea ........... 3’75 The coke market in Connellsville remains quotable at the set prices: Furnace, 6 dols.; 72-hour foundry, selected, 7 dols.; crushed, over 1 in., 7'30 dols., per net ton at ovens. The Fuel Administration has not made the recently expected ruling to allow a brokerage on coke as is allowed on coal, and it is quite doubtful now whether any action will be taken. OBITUARY. Mr. Greville Jones, who died from pneumonia at Middles- brough last week, at the age of 54 years, was works manager at the Port Clarence works of the allied firms of Messrs. Bell Brothers Limited and Messrs. Dorman, Long and Co. Limited, a position he had held since 1894. In his early days he was manager of the now defunct steel works at Rhymney, South Wales, from which district he hailed. He went north in 1891 on the invitation of the late Sir Lowthian Bell, to conduct experiments upon a new purifier at Port Clarence. He was a past-president of the Cleveland Institution of Engineers, and contributed papers of con- siderable metallurgical value to the Transactions of that institution and to those of the Iron and Steel Institute. Mr. James Howard Walker, M.I.M.E., F.S.I., mining engineer, died on Tuesday last week. The deceased gentle- man, who was in his 71st year, was the senior partner in the firm of Messrs. Kellett, Ellis, Walker and Rogers, mining engineers, of Wigan, and a brother-in-law of Sir Thos. Ratcliffe-Ellis. He served his time as a mining engineer and surveyor with the late Mr. John Rylands, at the firm’s Gidlow and Swinley Collieries, Wigan, and was asso- ciated with Messrs. Rylands as mining engineer until their Wigan collieries were dismantled on the mines being worked out. He acted as consulting engineer for a great many collieries in Lancashire, Yorkshire. North and South Wales, and also in Russia. He was a director of the Win- stanley Collieries Limited, and of the Ellerbeck Colliery Company Limited, Lancashire, and also of a group of York- shire collieries. As an authority on mining subsidence he was greatly in request for mining arbitrations and legal cases. Northern Colliery Officials* Mutual Aid Association.— At the 21st quarterly meeting held in Newcastle, the general secretary reported a large increase in the number of members. He stated that special efforts were being made to secure a right possessed by other mining organi- sations, namely—an associated hearing in placing matters before employers. CURRENT SCIENCE Laboratory Coal Washing Apparatus. Messrs. L. Crawford and G. A. Phillipson (Gas World, Coking Section) describe a new apparatus, and the method of using it, as adopted by them for the rapid control from the laboratory of the working of a washery. The apparatus is a modification of a well- known separator for minerals, and no claim is made for any great originality in design; but it offers many advantages over any other at present available. In use, the apparatus is about two-thirds filled with calcium chloride, or any other suitable solution of the necessary specific gravity. (This gravity must be determined by experiment for any particular class of coal and type of washer). A weighed quantity of the sample (up to 300 grms.) is then introduced into the upper portion of the separator, the internal stopper having been previously entirely withdrawn. The coal and solution are then thoroughly mixed, and the separator filled nearly full with the heavy liquid. After a few minutes’ settling, the internal stopper is inserted, and the settling is then allowed to continue for any necessary time, two to three hours being generally sufficient. When the intermediate liquid is clear, the internal stopper is cleaned from any deposit by a gentle rotary movement in the clear space, and firmly inserted in the upright position. The apparatus is then divided into two parts at the ground glass joint; the upper portion closed at the bottom by the internal stopper carrying the clean coal, the lower containing the dirt. The contents of the two portions are then separately filtered, washed, dried, and weighed. For the filtration, the authors use a 5 J- in. Buchner funnel, working under a suction of 2 to 3 in. of mer- cury, and thus obtain rapid filtration and thorough washing. The residue on the funnel is easily brought to an air-dry condition by continuing the aspiration of a current of air through the sample for a time, or, if it is desired to work on the dry samples, the residues may be transferred to the oven, after draining, and dried at 100 degs. Cent. In samples submitted for laboratory washing, no grinding is permissible. Pieces much larger than 1 in. mesh cannot be conveniently handled in the apparatus; but in the event of a sample being received containing large pieces, it is an easy matter to riddle a weighed quantity of the coal over a | in. or f in. mesh riddle, and to treat the portions over and under size separately. Acidity Determination in Mine Waters, etc. Mr. James J. Rankin (Metallurgical and Chemical Engineering) states that the following method for determining acidity in the presence of sulphates of ferrous and ferric iron, copper, aluminium, and manganese is new, and more accurate than the usual titration methods. It depends on the preliminary reduction of ferric to ferrous iron, and of copper to cuprous iodide, by the addition of potassium iodide, and the subsequent change of the free iodine formed to sodium iodide by the addition of the requisite amount of sodium thiosulphate, after which the ordi- nary titration with Na2CO3 is made. The equations for the above are as follow: — Fe2 (SO4)3 + 2 KT = KoS04 4- 2 FeS04 + 21 CuS04 4- 2 KI = Cu I 4- K2SO4 + I 214- 2Na2S2O2 = 2 Na I 4- Na2S4O6 The reagents needed are:—Potassium iodide C.P. (solution or crystals); solution of sodium thiosulphate, about 10 per cent, strength; standard sodium car- bonate solution (strength according to the percentage of acid in the solution to be titrated, from N/5 to N); and methyl orange. A definite volume of the solution to be titrated is measured out, and is diluted to 250 c.c., if the solution has not already this volume, an excess of potassium iodide being added. When copper is present, there will be a precipitation of cuprous iodide and formation of free iodine. Sodium thiosulphate is added in amount sufficient nearly but not quite to neutralise the free iodine present, followed either by filtering off cuprous iodide and washing three or four times with cold water, or by diluting to a definite volume, settling, and taking an aliquot part for determina- tion. To the filtrate or aliquot part add a slight excess of sodium thiosulphate as measured by the disanpearance of the yellow colour due to free iodine. When Cu is not present, no filtration is necessary after adding KI, and a slight excess of sodium thiosulphate is then added directly. The solution will now be colourless, or practically so, and, after addition of methyl orange, may be titrated as usual with standard sodium car- bonate solution. It is advisable when titrating solutions containing alumina and little or no iron to add ferrous sulphate before titrating. The acidity due to the hydrolysis of the aluminium sulphate present can be determined also, and a correction factor applied to give the true free acid, if necessary. Chlorides and nitrates have not been found to interfere. New Automatic Underfeed Stoker. In the new automatic underfeed stoker brought out by the American Smokeless Burner Company, Seattle, Washington (and described in The Times Engineering Supplement), there is a cast iron box with a stationary worm fixed in the centre, the top of the worm being pierced to permit the passage of the air required to support combustion. A circular combustion bowl rests upon the box, and fits inside it. On the lower side of the bowl are a series of screw-shaped blades, the pitch of which is in the opposite direction to the planes of the worm, extending into the bottom of the box, and serving to raise the coal when the bowl is rotated. The combustion bowl is kept in a central position in rela- tion to the box by rollers and the driving gear. To prevent overheating of the working parts, the box is partially filled with water, which also acts as a AND TECHNOLOGY. seal to guard against any back blast or leakage of the air supply. The heat and the draught dry this water out of the coal at a point about 2 in. or 3 in. above the worm feeding device. In the smaller sizes of stoker, the drive for the rotation of the combustion bowl is by a system of gears, the larger portion of which is enclosed in a box attached to the front of the stoker, while in the larger units worm drive is employed. Power is furnished by an electric motor, and a fan is provided to supply the draught. The only other essen- tial part of the stoker is a small tank which is kept filled with water by a float valve. When the stoker is in operation, coal is fed into the hopper at the top by hand or by a conveyor through an opening in the side. Thence it flows by gravity into the stoker box, which forms the body of the machine. The blades of the revolving bowl raise the fuel into the stationary bowl, where it is burned, the resultant ash and clinker passing mechanically upon the brick covered portion of the furnace, where the remaining heat is given up, the process being con- tinuous. The ashes are removed from the furnace as often as may be required; once a day is sufficient in some cases, but the larger units require more frequent cleaning. The stoker is placed in the back of the furnace, and is surrounded on all four sides by a level space floored with firebrick. Outside of this, on three sides, a course of firebrick rises at an angle of 45 degs., the rear section resting against the bridge wall, and the sides against the side walls of the boiler setting. The driving mechanism is placed outside the boiler front on the floor, and a horizontal driving shaft to rotate the bowl and a horizontal worm feed to deliver the coal from the hopper to the stoker are arranged in a bricked-in space at the right side of the ashpit. The motor driving the fan transmits power to these through gears and a chain and sprocket. The stoker is controlled by hand, where an attendant is always present, by steam pressure, or by a thermo- stat. In the first case, the motor is provided with a three-speed pulley to enable the attendant to change the rate of the coal feed to suit the character of the load; with the steam pressure method, an electric switch is operated whenever certain limits, which can be changed at will, are reached; and in the last, th© rise or fall of the steam temperature is employed to operate the switch, the limits in this case also being capable of variation at will. THE BY-PRODUCTS TRADE. Tar Products.—Pitch in London has a stronger tone this week, and the price, after standing nominally at 50s. for some time, is now averaged, in quotations, at 50s. to 52s. East Coast prices have advanced from 25s. to 27s. 6d. f.o.b., and the Manchester figure inclines to rise. No particular alteration relative to tar is evident at the present moment. In the matter of contracts a Halifax firm has undertaken to supply 16,500 gallons of refined or distilled tar at 3fd. per gallon at any station specified by the Caistor Rural District Council, but other supplies to the Council are contracted for at 4|d. The Middlesex County Council accepted a tender at 4|d. per gallon for highways work. From these quotations it is possible to gauge the sort of price level on which London and provincial authorities may have to base their expenditure on tar for road use. The probabilities are in favour of that level becoming a higher one. Solvent naphtha is firm, and heavy sort is scarce. Creosote does not alter much, but heavy oil is, perhaps, a shade easier in the London area. Cresylic acid is at a higher figure this ^eek. Other by-products are almost featureless, although business in all of them is proceeding. Current quotations are appended .-—Crude tar: London 32s. 6d. to 35s.; Midlands, 28s. to 29s.; North, 28s. to 30s. per ton, ex gas works. Pitch.- London, 50s. to 52s.; East Coast, 25s. to 27s. 6d. f.o.b.; Liverpool, 22s.; West Coast, 22s. to 24s. f.a.s. Solvent naphtha : Naked, London, 90-190 per cent., 3s. to 3s. 3d.; North, 2s. 9d. to 3s.; 90-160 per cent, naked, London, 4s. 3d. to 4s. 6d.; North, 3s. lOd. to 4s. Crude naphtha.: Naked, 30 per cent., S^d. to 8|d ; North, 6id. to 6|d. Refined naphthalene, ^30 to £32 10s.; salts, 80s. to 90s. Toluol: Naked, London, 2s. 4d. ; North, 2s 3d. Creosote : Naked, London, 4|d ; North, 4d. to 4|d. (Government price 75s. per ton, equal to 4|d. per gallon, f.o.r.) ; heavy oil, 4£d. to 4|d.; liquid, 4|d. Carbolic acid: Crude, 60 per cent., Fast Coast and West Coast, 3s. 4d. ; crystals, 39-40, Is. 3d. Cre=ylic : Casks, 95 per cent, 3s.; 97-99 per cent., 3s. 3d. ex works London and f.o.b. other ports. Anthracene: 40-45 A, 4|d.; 48-50 A, 6d., B, l|d. to 2d. Aniline oil, Is. 4d., casks free; salts, Is. 4d., drums free. Sulphate of Ammonia,— The position regarding sulphate supplies is practically a fixed one, and require- ments are met accordingly. It has not been possible to satisfy all such requirements precisely at the time needed, but that is the case with many other products in these days of labour shortage and transport difficulty. The prices, of course, remain at the scheduled figures, and nothing is yet heard regarding any official concession to producers. Fuel Economy Problem.—Addressing members of the Birmingham Rotary Club, Mr. A. E. A. Edwards dealt with the question of fuel economy, and remarked that of all sources of power the heat engine was the least efficient. It was a high-class plant indeed that gave 8 per cent, of the fuel over a week’s work. The average steam plant probably did not yield more than 1 per cent, of the value. The super-electric power stations on the coal fields were not likely to mature into anything practical, but, on the other hand, smaller stations situated in residential areas were far more likely to prove paying propositions. If, instead of turning 61 per cent, of heat into the atmosphere, we turned it into a heating system, they would put 90 per cent, of the waste heat value of the steam into the heating system. This heat would be distributed around the neighbourhood for domestic hot water. In fact, electricity would be a by- product, and heating and hot water supply the main source of income from the central station. The system was in use in America to-day. There was no reason why the exhaust steam from the factories should not be collected, metered and sold to the heating supply company.