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56 not exceed the following limits of the substances named: Moisture, per cent....-++erers 1 Volatile matter, per cent.....- 22 Sulphur, per cent ...--+-+++++ 1 Ash and solid matter, per cent. / (4) Bidders shall state in their pro- posals the least calorific value of the coal they propose to, furnish, when dried, in British thermal units per pound of coal. The calorific value named in the accepted proposal shall form part of the contract, and tests will be made for same on dried coal from representative samples of coal as delivered. Coal falling short _ in calorific value of the standard es- tablished by the accepted bid shall be reduced proportionately in price. (5) For each one whole per cent of moisture on laboratory test in ex- cess of the limit named, there shall be deducted 1 cent per ton from the contract price of the coal. (6) For each one whole per cent of ash and solid matter on laboratory test in excess of the limit named, there shall be deducted 1 cent per ton from the contract price of the coal. (7) For each whole half per cent of sulphur on laboratory test.in ex- cess of the limit named, there shall be deducted 1 cent per ton from the con- © tract price of the coal. (8) For each one whole per cent resulting from the addition of the ex- cess of moisture, sulphur, ash and solid matter, or any two of. them, when below the deduction limits named for each separately, on labor- atory test, there shall be deducted 1 cent per ton from the contract price of the coal. (9) Tests for calorific value shall be made with a bomb calorimeter, and all laboratory tests in accordance with the latest approved methods of the American Chemical Society. (10) The contractor,: or his au- thorized representative, may have the privilege of witnessing the weighing, sampling and analysis of coal, pro- vided that no undue delay is caused thereby, or the user may have the same verified by a competent and re- sponsible person; but in any event the weighing, sampling and analysis made upon the delivery of coal shall be final, ; (11) Failure of the coal to comply with the specified requirements and Original limitations shall be sufficient cause for rejection or cancellation of the contract. The foregoing specification is the Outcome of the author's endeavor to secure good steaming coal, the re- the. THE Marine Revicw sult of the study of available litera- ture and specilicat.ons and the, obset- vation of the working of coal in con- nection with its analysis. * transla- of the specification will be next tion in order: ni ' e - Steam coal may be anthrac.te, § bituminous, bituminous of peaty im its nature; local conditions and avall- able supply will determine which is used, but b.tuminous and semi-bitum- inous are by far the most largely and widely used, and the actual ditference between them is sometimes small. "kun of mine' coal is generally ac- cepted to mean coal that contains not less than 40 per cent of lump, no lump of less dimensions than a 3-in, cube. Coal may. leave the mine in this pro- portion, but in successive handlings may become go broken up as to gen- erally resemble "slack" in fineness. It has not, however, lost any of its orig- inal quality, and if it passes all tests and hres sat-sfactorily, no exceptions need be taken to the proportion of lump, which is hard to ascertain at the best. Other classifications of coal are as follows: ) 10 per cent is of a size the equivalent of a 3-in. cube, and the balance great- ef;. ege.,.or: nut,' in which, motsover 10 per cent 'is of a size equivalent to. a 1%-in. cube,.. and. the balance in larger sizes, but not exceeding -the equivalent of a 3-in.. cube; "steam nut," in which not over 10 per cent is of a s:ze equivalent to a Y%4-in, cube, and the balance in larger sizes, but not exceeding the equivalent of a 1!4-in. cube; slack," which is everything un- der the equivalent of a 14-in. cube, in- cluding dust, slate, dirt and any other objectionable or deleterious ; that may be present. " These classifications are not univer- sal on rigid; they are applied to the coal at the mine, and subsequent handling and transportation may pro- duce conditions which are intermedi- ate to the original ones, and also more or less fine coal, sometimes wrong- fully called "slack." From a consid- eration of these classifications it--will be obvious that "run of mine" will-be the cheapest coal of good quality for general steaming purposes. "yt The principal objectionable and del- eterious matters that occur in coal are the various natural combinations of sulphur, slate, crop coal, white scale and bone coal. Crop ¢oal is that part of the vein that has been exposed: to the weather. White scale: is carbonate of lime and an adulterant.' Bone coal 1S a portion of the vein that is inti- matter "Lump,"..in which not over- mately mixed with fine slate OP ee All deleterious and objectionable mat- ters are fairly visible to a trained eye and should be separated from the coal at the mine. ; The weight of coal as delivered {o the user will vary with the amount of moisture it has given up or absorbed from..the time it has been mined yp. til it is delivered. It may come from the mine wet and drain out or dry in transportation, or it may come from the mine dry and absorb moisture from. exposure to rain and snow in transit. In well-handled and_ trans. ported coal the moisture will usually vary from one-half of 1 per cent to 1..per.cent..,.In a, test. Om, @ meen sample -the author found that about 5 per cent of moisture could be carried without dripping. It is necessary to limit the amount of moisture that will be accepted, in order to insure careful handling and transportation. It is sometimes thought hat moisture im- proves the burning and heating value of coal; for those who think so it is better to add the moisture and not pay from $3 to $5 a ton fon it, It seems Hardly necessary to say that moisture not only' has no_ heating value, but uses up' a certain amount of otherwisé effective coal in evaporating it. SAH A representative sample ~ selected from the coal as delivered should con- tdin as nearly as possible the same proportion of lump, fine coal and dirt as the shipment. By selecting from various depths it may also be taken sO as to contain about the average percentage of moisture. Analyses made on lump coal only will show very much better results than an avet- age sample, and analyses made on . fine coal only will give -poorer re sults than the average. The reason is obvious, as the lump coal comes from the purest and most solid part of the vein, and is largely free from slate, dirt and sulphur compounds. The fine coal, on the contrary, 1s mixed with the deleterious and ob- jectionable substances. Many specifi- cations give elaborate directions for pulverizing, quartering and re-quaf- tering the sample for analysis. It is important that the sample should be representative of the general and av- erage condition of the coal, and that it should be placed in fairly tight te ceptacle to prevent the evaporation Of absorption of moisture; these precat- tions being taken, the chemist cam be depended upon for further details. The volatile matter in coal is gef- erally and principally hydrogen, OXY