PC-NRLF NOTES AND FORMULAE FOR MINING STUDENTS GROSBT iOCKWOOD & SON. REESE LIBRARY or THE'" UNIVERSITY OF CALIFORNIA. ' "- * ^ffrl^tu^, 1 88 4 A c cessions No^-f/.^ Shelf No. \ , m ' NOTES AND FORMULAE FOR MINING STUDENTS. ' NOTES AND FORMULAE FOR MINING STUDENTS BY JOHN HERMAN MERIVALE, M.A. CERTIFICATED COLLIERY MANAGER J MEMBER OF COUNCIL OF THE N. OF ENGLAND INST. OF MINING AND MECHANICAL ENGINEERS ', AND PROFESSOR OF MINING IN THE DURHAM COLLEGE OF SCIENCE, NEWCASTLE-UPON-TYNE. IStttton, ( UNJYKKSITY LONDON : CROSBY LOCKWOOD AND SON, 7, STATIONERS' HALL COURT, LUDGATE HILL, 1888. [All rights reserved.} K LONDON I BRADBURY, AQNKW, . 0^ ^ C ^ w fc J3 -i-T . S) -* G ' rt j'n c CKETARY TO BOARD C EXAMINATIONS. dress and Date on whl aminations usually hel ^askell W. Peace, jng Street, Wigan. December. if 5 s ^ aTt/5 ^ C \o^ Wm. Saunders, e Wardwick, Derb' October. Robert Calder, .enfrew Street, Glas May. fc ^.c**!^ c^ :w "W ^ c^O iS K >ll 6 "I r* & a^s| ^o^ b| ugg -*- 1 (U OO fe"f^ 3 fc/3 tf w o Wl aa| 2 C/3 - (L) ^ OK ri| 51 1-1 g < MD 111 ^ ^ rt O "3 O 00 of . -* t/r c all goS & U &: H the Candida > for Examin , the Mines' ; e changed fr III yi ^6 CO ll" PH ^ C K -J """ u CL, gj 333 fj till si ^ ^ I "1 - *J= & c rt 9 ,0 .1 Q.) ^ > K 'H t '^ r-- *5 kflj-; Q 00 *2 o C -^ 1e S .S fcX)_, '-3 o Q 5? eS Q rt 45 P .2 11 ** till c z z "o .^j c *" rt C/3 ^ t: 1 s tc O 3 is W: i w s * * 1 w rt6 g INSPECTORS, &*c. t ADDRESSES. T ff- id ~2 >* "So oT <= -4-j* C o ? -c ^G l^ 1 s Ci Sr 8 ^ " do | p a H^^ W ^A P53 A^ ^G j? [ *> o c/a oo" ^ HJ? 1> l H H U ro 00 OO rt m xoo *w 5t3 ri I-H Q i4 '"< U ~ . CH rC ^ ctf ^ ci jTl .5 g . o oo ^11 (U ci W ^^ s ^ . 00 1 , w PQ| g ^ <2 fl o3 1 J3 *w Ctf C-H 3 S! | 5 5 2 o * CD o THE COAL FIELDS OF GREAT BRITAIN AND IRELAND. THE rocks forming the earth's crust are divided by geo- logists into two groups, viz. : The Aqueous or Stratified ; The Igneous or Unstratified. These groups are subdivided into numerous systems, and in one of the systems of the stratified group coal is found in such large quantities as to have conferred upon it the title of the Carboniferous System.* The table following shows the systems of the stratified group and their subdivisions in descending order, beginning with the superficial deposits down to the lowest known depths. At the commencement of the Lower Carboniferous period (upper old red sandstone) the greater part of the British Isles, south of Perth, appears to have been occupied by two seas, separated the one from the other by a ridge of land passing through the centre of Wales, Shropshire, Worcester- * It must not, however, be supposed that coal is found only in the Carboniferous system. As a matter of fact, it occurs more or less in every one of the Aqueous divisions. For example : In the Tertiary we have the lignites worked for many years at Bovey Tracey, in Devonshire ; and the lignites, brown coals, and pitch coals of the continent. The Cretaceous contains lignite and bituminous coal in Spain, Germany, New Zealand, and South America. The Jurassic : The Kim-coal of Kimmeridge, the moorland coal of Yorkshire, and the coal of Brora in Sutherlandshire. Besides these, there are many lignites and bituminous coals worked on the continent. The coal-fields of India, and a part of the Australian coal-fields, are in the Triasso-Jurassic formation. The Permo-Carboniferous furnishes coal in North America, Bohemia, and Autun in France. In the Devonian are situated some of the coal- fields of N. W. France, as in Mayenne. From the Silurian, coal has been worked in Portugal. SEDIMENTARY ROCKS. TABLE I. TABLE OF THE CHIEF DIVISIONS RECOGNIZED IN THE SEDIMEN- TARY ROCKS OF BRITAIN. Those Formations which occur in Northumberland and Durham are denoted by asterisks. TABLE OF STRATIFIED ROCKS. e Break (uncon- Represented locally by a break ocks^ formity). in the succession. [N.B. The figures give maximum thicknesses only.J PERIODS SYSTEMS. FORMATIONS. LIFE-PERIODS. * ( W> I POST-TERTIARY or ^'-5 -I PLEISTOCENE |a 1 (25 ft *Peat, Cave and Valley Gravel Deposits. * Brick-earths and Loess. * Raised Beaches, &c. * Boulder-Clay and Gravels Kange of Invertebrata and Plants in time Range of Fossil Fishes in time Range of Fossil Reptiliain time Footprints of Birds? Range of Fossil Birds in time Range of Fossil Mammals in time II 1! ss & |PUO=ENE ( TO ^^^^ >" d C '<" Dominant types, Birds and Mammals. I MIOCENE (125 ft.) | Bovey Beds (?). f Fluvio-Marine Series. 1 EOCENE (2,600 ft.) 4 Bagshot Beds. C London Tertiaries. SECONDARY or MESOZOIC. ,Maestricht Beds. (Chalk. CRETACEOUS J Upper Greensand. (7,000 ft.) 1 Gault. Neocomian. VWealden. JURASSIC ( (3,000 ft.) Purbeck Beds. Portland Beds. Kimmeridge Clay. Coral Rag. Oxford Clay. Great Oolite. Inferior Oolite. Lias. Dominant type, Reptilia. f Rhsetic. TRIASSIC \ Keuper. (3,000 ft.) 1 Muschelkalk. l*Bunter (?). ( PRRMIAM ( * Red Sandstone and Marl. { ( 5 oo P S R "r f ,, fei^''^ Dominant type, Fishes. u o 3 2 > & < *5 04 PL, CARBONIFEROUS (20,000 ft.) r *Coal Measures and Mill- stone Grit. *Carboniferous Limestone or Bernician Series. *Tuedian and Basement Beds or Up. Old Red Sandstone. '.oft i u) DEVONIAN ( Devonian. (5,000 to 10,000 ft.) ( Old Red Sandstone. 1 Dominant type, INVERTEBRATA. ^SILURIAN ( Upper Silurian. (3,000 to 20,000 ft.) (. LowerSilurian orOrdovician CAMBRIAN ( n , . (20,000 to 30,000 ft.) { Cambnan - PRE-CAMBRIAN.&C. C T, r , . (30,000 ft.) (Pre-Cambnan. [G. A. LEBOUR.] COAL FIELDS OF BRITAIN. shire, and south Staffordshire, into the Eastern Counties. These seas were gradually filled up with limy ooze, sand, and mud ; so that, at the commencement of the Upper Carboniferous period (coal measures), they had become two large swamps. In these swamps the vegetation grew which now forms our seams of coal. Each seam marking a period when the swamps were above water, the intervening beds of sandstone and shale a period when they were below. At the close of the Carboniferous period the earth's crust in these districts was upheaved along several parallel east and west lines. Taking the North of England as an example, two of these axes of upheaval passed, the one to the north, the other to the south, of the present Newcastle coalfield. The denuding agencies of rain, frost, &c., planed off the tops of the ridges, sweeping away the rocks lying high up in the series, together with the seams of coal ; the result being that the Newcastle coalfield occupied the eastern portion of a trough of coal measures extending from the west of Ire- land to the German Ocean ; and this trough was separated from similar troughs to the north and south (now occupied in part by the coalfields of the south of Scotland and York- shire, &c.) by tracts of country denuded of their coal. Upon these troughs of coal measures and barren intervening coun- try the Permian, the next formation in ascending order, was deposited. Again, there was a period of upheaval ; but now along lines running north and south. One of these ran to the west of Newcastle, and formed the Pennine chain, or great central ridge of the North of England. Again, the agents of denudation set to work, planed down the arch and separated the Newcastle coalfield from that of Whitehaven. It is to the intersection of these two series of axes of upheaval, approximately at right angles the one to the other, that the basin shape of our coalfields is due ; while the dis- severance of these basins the one from the other has been the necessary consequence of the planing down and sweep- ing away of the arches by the action of rain, ice, &c. The fields of coal now left to us by denudation are shown in the following table. The names of the districts are not those of the separate basins, but the groups into which they have been divided under the Coal Mines Act. MINING STATISTICS. 2RS |-| 00 O CM* t*. ^M co vO ONO ^ to < ON i^* i 01 ONCO t^ T^* c^ t^ cs t^* M N O N -* >o rj->o w ON O o >o o ""> if) \r^ *$ ir> f} *$ N ON -> i-O M +* M TJ- M ONfOO O ON O vO to ON ON t^ co 'OOOOO'OCX)!-' vO O ON 00 U^ON 'OCX) "ivO ON O CO P4 CO M t-O M 00 t^ O O ON t^ t^OO I I ?*?! vo O O rfvo M ooo" +? OO vo CO I I vo COO I M CO I-" LO M CO I >-< rj- O co O co I O -< ON ^ w | 0~0~M~ ri- t^ M -H C^l !O vo' tN ONOO rj- 10 ON ^~ vo~ >o oo" vo" cT ri oo" co ON vO GO OO O ONVO t^. OOO _ M M CS I 00 O M hc R r r-^ vO ON r^N OOMDiooONt^ ON f^ TJ-NVO ^.M rj- o tovo ON I ^~ t^ co ON ON tC rf vo" | ON o" co toco ONr>.ONt^Noo iw w OO HiVOVOOCN i-T co to i-Tvo" co co W V CO co *> co co ON TEE NEWCASTLE COALFIELD (NORTHUMBER- LAND AND DURHAM). Section of the Strata. The Post Tertiary, all four divisions of which are found ; but more especially the Boulder clay, which consists, for the most part, of stiff blue and brown clays, with boulders of limestone, sandstone, basalt and porphyrite. It covers almost the whole of the coalfield. The Permian Formation, about 600 feet thick. It extends over the East and South- East of Durham. It rests uncon- formably upon the coal-measures, and consists of the mag- nesian limestone, and the yellow sand (often very wet and loose), and produces limestones ; but no coal. The Coal Formation probably extends (either at the sur- face or beneath more recent formations) over the whole of Durham or Northumberland, excepting the Cheviot district. It may be subdivided into i. The Upper Coal Measures, from the base of the Permian to the roof of the High Main Seam, about 1,100 feet. Here are found the Hebburn Fell, Five Quarter, and Three Quarter Seams. 2. The Middle Coal Measures, from the roof of the High Main to the floor of the Brockwell, about 900 feet. Here are found all the best * seams of the district, some sixteen in number, of a thickness, in the aggregate, of about 50 feet, discarding those less than 18 inches. Fifty feet, however, will not be found in any one section ; but 30 feet may be taken as an average. 3. The Lower Coal Measures and millstone grit formation, from the floor of the Brockwell to the roof of the Fell-top limestone, perhaps 600 feet, contain no seams of any present * Amongst these the following may be mentioned : The High Main of Northumberland (a house coal) is the Three Quarter of the Hetton district (an inferior coal) and the Shield-row of Pontop (a gas coal). The Metal coal and the Stone coal of the Tyne run together to form the Grey Seam of Northumberland (a steam coal) and the Five NEWCASTLE COAL FIELD. value. 4. The Bernician, from the roof of the Fell-top limestone to the base of the Harbottle grits, 2,500 to 8,000 feet. Several seams of coal are found here ; but they are variable in quality, thickness, and extent. The best known are, perhaps the little limestone coal, and the Shillbottle seam. 5. The Tuedian beds from the base of the Harbottle grits to the Silurian formation. By the term, " The Newcastle Coal Field," only the upper and middle coal measures are usually meant. These extend approximately from the Coquet to the Tees, and may be divided into Exposed coal field . . 460 square miles. Beneath the Permian . . 225 Beneath the sea . . . in 796 square miles. It was estimated, in 1870, that the upper and middle coal measures contained . . 7,452,250,000 tons. The limestone coal . . . 580,000,000 8,032,250,000 Quarter of the Hetton and Pontop districts (a house coal). The Metal coal produces house coal. The yard seam of Northumberland (steam) is the Main coal of Hetton (house) and the Brass Thill of Pontop (a gas coal). The Bensham of Northumberland (steam) is the Maudlin of Hetton (gas and house). The Five Quarter of Northumberland (steam) is the Low Main of Hetton (steam and house). The Bensham and Five Quarter run together to form the Hutton Seam of Pontop. The Low Main of Northumberland (steam) is the Hutton Seam of Hetton (house) and the Main coal of Pontop (coke). The Beaumont of Northumberland (unworked to the east) is the Harvey of Hetton (gas and coking) and the Towneley of Blaydon (house coal). The Stone coal and Five Quarter, found in the S.W. of Northumber- land (steam and house coal) unite to form the Busty Bank of Pontop (coking and gas coal). The Brockwell, not worked in E. Northumberland, is a house coal at Blaydon and a coking coal about Brancepeth. NEWCASTLE COAL FIELD. including all seams above 18 inches thick, and not more than 4,000 feet deep. Since that date about 400,000,000 tons have been worked. Dykes. The principal whin dykes run east and west, and " are remarkably uniform in lithological composition. They are, as a rule, close-grained basalts, deep blue when freshly broken, and weathering to brown or red." The following may be mentioned beginning from the North : Acklington, Bedlington ; Hartley ; and Coley-Hill, in Northumberland ; Hebburn, the southern extension of Coley-Hill ; Hett ; and Cockfield in Durham. Troubles. These, too, run for the most part east and west. The most important, beginning from the north, are: Dipper South, of about 50 fathoms, between Newbiggin and North Seaton ; the Ninety-fathom Dyke, a dipper North, which runs from Cullercoats, between Killingworth and Gosforth Collieries south of Newburn, through Whittonstall to a little west of Minsteracres, where it dies out ; Stublick, a dipper North, which, starting from a little to the south of Cor- bridge, runs west into Cumberland ; and Butterknowle, from Wingate Grange to Butterknowle, a dipper South of 40 fathoms. Mineral Products, 1881. Coal, 35,592,420 tons from 365 collieries. Iron ore> 70,77 1 tons from Weardale. Fireclay, 438,25 1 tons, Durham principally. Lead ore, 17,467 tons; Silver, 54,036 oz. ; Pyrites, 5,466 tons; Barytes, 5,435 tons: from the Bernician. Limestone for furnace linings from Permian ; for a flux and agricultural purposes from Permian and Bernician. Basalt for road metal from dykes. Sandstone for building, grind- stones, and filters. Cement stones from the Tuedian. Since 1881 Salt has been pumped near Middlesborough ; but there has been a decrease in the production of iron ore, and lead The important commercial position of this district is due NEWCASTLE COAL FIELD. i st. To the numerous seams of coal, which are thick, produce the best coal of every kind, and are cheaply worked. 2nd. To the position of the coal along a coast line, indented with many natural harbours. 3rd. To the near neighbourhood of the Cleveland ironstone (Lias). 4th. To sundry minor advantages, such as the lead, fire- clay, and building stones ; and now the salt (Trias, or upper Permian) found in the neighbourhood of Middlesborough, at a depth of about 200 fathoms. The Drawings and persons employed in Northumberland and Durham during the seven years, 1879 85, have been : TABLE III. TONS. PERSONS EMPLOYED. Northumberland * JJ 17 QOO South Durham 17 146 64.4. 4Q ?6 i Northumberland 6 850 162 21 OA8 1880 ' North Durham 7O7 5 846 18 528 South Durham 20 087 500 C-7 224. Northumberland 7 O74 577 OJ>^' i 't 22 74O 1881 North Durham 6 086 030 18 481 South Durham 21, 530 013 54 810 Northumberland 7 060 783 27 ?68 1882 North Durham . 7 458 006 IQ ?2Q South Durham 21,780 808 CC 060 Northumberland 7^27 o65 27 7Q3. 1883 North Durham. .... 7 738 87O ^O>/Vj ; IQ 621 South Durham 22 I 3.Q 565 C7 o67 Northumberland 7 5l6 OCX 2C 42"? North Durham 7 618,2^4. 2O 4O 3 20,034,040 c6, ^33 [ Northumberland 7 354 776 26 510 188=;. North Durham 7,340,007 10,712 South Durham . 2O,3Q7 317 cc 720 COAL FIELDS, TABLE IV. THE PRINCIPAL COAL FIELDS OF THE WORLD. Estimated area in square miles. Estimated thickness in feet. Produce in 1880, in millions of tons. Consump- tion in 1880, in millions ol tons. Produce per man employed in 1880, in tons. United States Australia 196,000 30,000 2O,OOO 7,500 5,500 2,500 2,OOO 1,500 1,000 550 2O 2O 35 5o 60 60 70-3 I-8 7 1 49 '3 1-31 2-9 59'2 19-4 16-9 i6 - o 0-48 275 70T I30T 56-8 28-5 I2T 14*6 337 295 1 66 164 China British North America (1884) . Great Britain British India (i 883)... Russia Prussia . . France Belgium Austro-Hungary New Zealand (1884) New S. Wales (1884) Composition of Coal. Coal varies in composition as it passes from lignite, the first stage in its production from vegetable matter, through its subsequent stages into anthracite. This is shown in the following table, after Thomas, " Coal, Mine-gases, and Ventilation," p. 6. TABLE' V. ' Carbon. Hydrogen. Oxygen. Nitrogen. Sulphur. Ash. Wood 5o - o 6-0 4I'C I 'O I'C Lignite 56-0 House Coal ... 8i'o Steam Coal ... 89-0 Anthracite ... 91*5 Cannel j 80 'o 5'0 5'o 4-0 3-0 6-0 25-0 8-0 2'5 i '5 7-0 5 '5 o o 5 2'0 I 'O I'D I'O I'D I0'5 3'5 2'5 2'0 4'5 Produce of Coal Seams, &c. The produce depends upon the specific gravity of the coal (1-25 to 1*50), the system of working, and the number of faults, balks, etc. A rough and ready rule is to calculate WEIGHT OF ORES. the produce at 100 tons per inch per acre, which leaves an ample allowance (about 25 per cent.) for loss of every kind. The weight in the seam per inch per acre = specific gravity x 101. At a colliery in Durham, working the Harvey Seam, 3 feet 6 inches thick, 5,185 tons per acre were got when working long wall ; 5,052 tons bord and pillar. TABLE VI. WEIGHT PER SQUARE FATHOM ONE INCH THICK OF VARIOUS ORES IN POUNDS. Gold Native 3,281 *2l Zinc Red Oxide I OI2'tjO Silver do Copper do Vitreous Copper 1,875*00 1,66875 I.CXO'OO Blende Zinc Sul- \ phide / Nickel Glance 750-00 I do6"">c Copper Pyrites 787-50 Cobalt Glance Q-27'CO Red Copper 1,106-25 Iron Pyrites 012-71; Malachite (Carbo- ^ Magnetite 1,016*25 nate of Copper)... J Tin Oxide (Cassiterite^ 712-50 i,2s6-2<; Arsenical Iron Ore ... Specular do. ... 1,068-75 QI2*7C Galena (Lead Sul- \ Haematite ... 7 ^O *OO Dhide) 1,406-25 Pitch Blende (Ura- \ Lead Carbonate | nium) I 1,312-50 (Cerussite) f I,2OO'OO Baryta 7CQ'OO , _J The Coal Commission of 1871, estimated that 146,480,000,000 tons of available coal were left in Great Britain and Ireland ; including no seams less than one foot thick, or at a greater depth than 4,000 feet. Since then, about 2,000,000,000 tons have been worked. Authorities ; "Extent and Duration of the Nor them Coal Field;" T. Y. Hall, Trans. N.E.I., ii. 104. "Rivers, Ports and Harbours of the Northern Coal Field ; " T. Y. Hall, Trans. N.E.I., x. 41. " Outlines of the Geology of Northumberland and Durham," Lebour; "The Coal Fields of Great Britain," Hull. " Coal : Its History and Uses," Green, Miall, etc. Several Papers in the "Trans. N.E.I. Mining Records," Hunt. " The Coal Seams of the North- umberland and Durham Coal Field," J. B. Simpson. The Report of the Coal Commission, 1871. The Reports of the Inspectors of Mines. THE STRENGTH OF MATERIALS; Some approximate formulae. STRAIN. FRACTURE. Elemen- ( Extension. Tearing. (Ropes.) tary. (Compression. Crushing. (Short Columns.) r ( Distortion. Shearing. (Rivets.) m " { Twisting. Wrenching. (Shafts.) (Bending. Breaking across. (Beams.) The factor of safety is the ratio that the breaking strain should bear to the working load; it depends upon the nature of the load and the material, as follows (with some ex- ceptions) : Material. Dead Load. Live Load. Metal 3 6 Masonry and Brickwork 4 8 Wood and Hemp 5 10 The proof strain should be from to \ the breaking strain ; or twice the working load. Round Ropes. W = Breaking load in tons. C = Circumference of rope in inches. (L) W = o-25C 2 .'. C= \f ^- for hemp ropes. /w ( 2 .) W= i*5oC 2 .'. C= 'y for iron wire ropes. /Ty~ for crucible steel wire ropes. O (4.) W= 4C 2 .*.C= /Y for improved plough steel wire ropes. STRENGTH OF MATERIALS. 17 As the sizes of ropes are usually referred to their circum- ferences, the following formulae will be useful : c = Circumference in inches. A = Area in square inches. d = Diameter in inches. (5-) c= (6.) A =7854 d' = ='0 4 In calculating the size of rope required to support a given weight, the weight of the rope itself must be taken into account ; but the weight of the rope cannot be calculated until its size is known. If c = circumference of rope in inches. w = weight roughly in Ibs. per fathom. c 2 (8.) w=- hemp. 4 c 2 (9.) w = - iron or steel. Combining these formulae with formulae (i), (2), (3), and (4), we get (10.) c= ^ / o'25_ F for hemp. M 4 x 2240 (n.) c= ^ / r5 F for iron. M 1*2 x 2240 (12.) c= ^ / _3_ F for crucible steel M i'2 x 2240 1 8 STRENGTH OF MATERIALS. (13.) c= i^l 4_ F for improved plough steel. M i '2 x 2240 Where c = circumference of rope in inches. L = Load, viz., full cage and chains in tons. M = Factor of safety (from 6 to 10). F = Depth of pit in fathoms. At a certain depth, the weight of the rope will be equal to the safe working load. Thus for round crucible steel ropes with say 8 as factor of safety, we see from formulae (3) and (12), that the limit of depth in fathoms is : 3 c 2 2240-3- 2 = i, 008 fathoms. I "2 When the time arrives to work mines at such depths, taper ropes must be used, see formulae (14) and (15), or the mineral raised in more than one lift. Round Taper Ropes. Are made of a decreasing size from the top to the bottom, so that they may be as strong at the top, where the strain is greatest, as they are at the bottom, where the strain is least. A = Area of rope at any point in square inches. a = Area of rope at bottom end in square inches. w = Weight of one cubic inch of the rope in Ibs. (For an iron or steel rope w = o'i4, for a hemp rope w='043. Both these numbers are approximate only, as the weight depends partly upon the size of the rope.) L = Safe load in Ibs. per square inch of section of rope (say, Iron, 7,000; Steel, 11,500; Plough Steel, 13,440; Hemp, 740). D = Distance in inches from A to a. W = Weight of rope in Ibs. 6 = 2*7182. STRENGTH OF MATERIALS. wD (14.) A = ae (15.) W = /wD \ = La\e L -i/-L(A- (A-a). To avoid the use of logarithms, the following table of the wD values of e for distances from 10 to 600 fathoms is given. By it the dimensions of a round plough steel taper rope at points 10 fathoms apart from the bottom to the top can be calculated. TABLE VII. Distance Distance Distance Distance from A from A from A from A to a in wD to a in wD to a in wD to a in wD fms., i.e., Y fms., i.e., T fms., i.e., j fms., i.e., j D e D e 1 " D e D e 6x 12 6x12 6x 12 6X12 IO 1-0075 160 1275 310 2617 460 1-4119 20 1-0151 170 1359 320 2712 470 I -4226 30 I -0227 1 80 1445 330 2808 480 i "4333 40 I "0304 190 1531 340 2904 490 i -4441 50 1-0382 200 1618 350 3001 500 i '4549 60 I "0460 2IO "1705 360 3099 510 i -4726 70 I'0539 220 -1793 370 3198 520 1-4769 80 I -0618 230 1882 380 3284 530 i -4880 90 I -0698 240 1972 390 '3397 540 i -4992 100 1-0778 2062 400 3498 550 1-5105 no 1-0859 -2153 410 3600 560 1-5219 120 I -0941 270 2244 420 3702 570 1-5333 130 I-I024 280 2336 430 3805 580 i '5449 140 i*iio6 2 9 2429 440 3909 590 I-5565 150 1-1190 300 2523 450 4014 600 i -5682 Flat Ropes. Are formed of two or more round ropes stitched together, and their strength may be calculated accordingly, a deduc- tion being made of about 10 per cent. C2 20 STRENGTH OF MATERIALS. Another rule. C. M. Percy, " Mechanical Engineering of Collieries," p. 71, says : Round Ropes. C a x 4 charcoal iron. C a x 6 crucible steel. '18.) C a x 10 plough steel. Flat Ropes. Width x thickness x 35 charcoal iron. Do. x do. x 55 crucible steel. Do. x do. x 70 plough steel, gives the safe working load in cwts. ; the dimensions are taken in inches. Chains. W = Breaking load in tons. D = Diameter in sixteenths of an inch. D 2 (22.) W = .*.D= voW. 9 In this district, the factor of safety used for cage chains is probably about 10, not 6. Cast Iron Pipes. Th = Thickness of metal in inches. D = Diameter of pipe in inches. H = Head of water in feet that will burst pipe. / \ -rr_72,oooTh . rpi _ DH D 72,000. If VV = Weight per linear foot of cast iron pipes in Ibs. D = Outside diameter in inches, d = Inside do. do. (24.) W=2- 4S (D 2 -d a ). The weight of the two flanges may be taken as equal to one foot of pipe. Boiler Shells. Th = Thickness of plate in inches. D = Diameter of boiler in inches. P = Bursting pressure of steam in Ibs. per square inch. STRENGTH OF MATERIALS. 21 / 2 ?\ p_5 ( (a) Iron Boilers. D,oooTh . ,p, _ PD / s : n _j e r ; ve ted^ Vov f {26 } P- 6( . . x ii ^siii^ic iivcLCuy. 50,000 D o o o Tli "P T3 \^ u v - 1 - D 60,000 (b) Steel Boilers. / \ -n 7o.oooTh , PD / -, *j\ (27.)?='? _.'.Th = - (single riveted). 70,000 (28.) P = 9> oooT1 V.Th== PD (double riveted). D 90,000 x Though 6 is usually considered sufficient as the factor of safety, 8 agrees better with the practice of this district. Boiler Tubes (Iron). Th = Thickness of plate in inches. D = Diameter of tube in inches. L = Length of tube in inches. P = Collapsing pressure in Ibs. per square inch. LD Masonry Pillars. W = Crushing load in tons. A = Area of red brick pillar in square inches. (30.) W=- 3 8A.-.A = -J See also T in Table IX. Beams. L = Length of .beam or span in inches. B = Breadth of beam in inches. D = Depth of beam in inches. W == Breaking load in tons. K = Coefficient of rupture. (See Table VIII.) 22 STRENGTH OF MATERIALS. (31.) W = - when one end is fixed, and the other end loaded. (32.) W= - when one end is fixed, and the load distributed. (33-) W = | -- when both ends are supported, and the load is in the centre. /T7- ~D"P\2 (34.) W = j - when both ends are fixed, and the load is in the centre. oT7-T)-r\2 (35.) W = j- when both ends are supported, and the load distributed. (36.) W= j - when both ends are fixed, and the load is distributed. Circular beams with radius R inches; substitute 47R 3 for BD 2 in the above formulae. TABLE VIII. VALUES OF K FOR DIFFERENT MATERIALS. Wrought Iron .................................... K = 3'4O Cast Iron .......................................... K = 2'3O English Ash ....................................... K = o'95 Beech ............................................... K = cr65 Fir(Spruce) ....................................... K=O'6o English Oak ....................................... K = o'75 African Oak ....................................... K=i'io Red Pine .......................................... K = cr65 Yellow Pine ...................................... K = o'5o Memel Pine ....................................... K-o'6o Pitch Pine ......................................... K = o75 For most purposes, the breadth and depth of the beam should be proportioned, so that, in round numbers, the depth be about i^- times the breadth. STRENGTH OF MATERIALS. 23 If then we put D = i'5B, (31) becomes and similarly for the rest. Molesworth (pp. 119 120, i9th ed.) gives for cast and wrought iron girders : Cast-Iron Girders. D = Depth of girder in inches, including flanges. A = Area of bottom flange in inches (i.e., width x thick- ness). S = Span in inches. W = Breaking weight in tons. Supported at both ends with load : (38.) On centre, W = 2 -^ . . E (39.) Distributed, W = ^^ .*. A Area of top flange if the load is applied on the top = A S ^ If applied on the bottom flange = . And D = (about). 2 12 Wrought-Iron Plate Girders. L = Span in feet. W = Weight distributed in tons. D = Effective depth of girder in feet. S = Strain on top and bottom flange at centre in tons. WL WL (40.) S = -g !5 .-.D=-gg In compression, iron may be strained 4 tons ; in tension, 5 tons per square inch. Long Square Columns length more than 30 times diameter. W = Breaking load in tons. B = Breadth in inches. L = Length in feet. K = Coefficient of rupture. 24 STRENGTH OF MATERIALS. K for dry Memel= 7-81. K for dry Oak = 10*95. If in a damp situation as pulley frames, K must be taken rather less, say 6 and 9 respectively. Dams, Tubbing, &c. k = Thickness in inches. r= External radius in inches. T = Ultimate crushing strength in Ibs. per square inch (See Table IX.). p = Head of water in Ibs. per square inch. Cylindrical Dam, Walling, or Tubbing. Spherical Dam. 10 is -taken as the factor of safety, and is allowed for in the formulae. See " Internal Stress in Cylindrical and Spherical Dams," by W. Steadman Aldis. Trans. N.E.I., xxxii. TABLE IX. Wrought-Iron ........................... T= 38,080 Cast-Iron ................................. T=io7,52O Beech ....................................... T= 8,500 Oak ............ ........................... T= 10,000 Pitch Pine ................................. T= 6,500 (?) Brick ord. red ........................... T= 800 Do. Stourbridge fire ................. T= 1,717 Sandstone ................................. T= 2,185 to 7*884 Concrete ...................... _______ about T= 2,000 (Molesworth. ) STRENGTH OF MATERIALS. 25 Another Formula for Cast-Iron Tubbing. x Required thickness in feet. P = Vertical depth in feet. D = Diameter of pit in feet. PD (44.) * (GreenwelPs " Mine Engineering.") The following books may be consulted : Barlow's " Strength of Materials " ; Box's " Strength of Materials " ; " Materials and Construction," by Campin, Weale's Series ; and Molesworth's " Pocket Book of Engineering Formulae." TIMBER. THE most suitable timber for pit props, baulks, &c., is fir and pine, because though weaker and less durable than oak, elm and some other timber it is light, cheap, straight, and elastic. The mining timber used in the North of England comes chiefly from Sweden, and is the product of the Scotch fir (Pinus sylvestris) and the spruce (Abies communis), known to the trade as "red and white wood" respectively. A good deal of native-grown larch (Abies larix) too is used, more especially for sleepers. Beech, grown in the district, is used for nogs. Pitch pine (Pinus rigida) from North America, for pump spears, pulley frames, &c. Timber Measure. Props are bought and sold per 7 2 running feet, the price depending upon the diameter. Larger sizes per cubic foot, per load, or per standard. To calculate the number of cubic feet in round timber : gird the log round the middle with a string, and one fourth of the girth squared x the length = cubic content. If the log be very irregular, divide it into several lengths and measure each separately. i load= 40 cubic feet, unhewn timber. ^ =50 squared = 600 superficial feet, in i inch deals or planks. = 400 ij and so on, equal in each case to 50 cubic feet. i square of flooring = 100 superficial feet. Battens are 7 inches wide, deals 9 inches, and planks ii inches. TIMBER. 27 i standard = 165 cubic feet square timber. = 150 partly squared. = 100 round. w =1500 running feet of 3 inch. = 1200 4 = 1000 5 A standard of timber occupies about the same space on board ship as 3} tons of coal ; but this partly depends upon the shape of the ship. Cost of Timbering. This is very variable, depending upon the conditions oi the mine and the price of timber. Gallon cites Grand-Combe $\d. per ton of coal. Evrard, a colliery in the Pas-de-Calais, 10*088^. ; and one in Bel- gium, is. $d. Drinker, quoting Rhiza, gives the consump- tion of 54 German mines from 1*35 to 8*58 cubic feet of timber per 100 cubic feet of coal. Average, 3-40 cubic feet. At a colliery in Durham, using larch, the cost, in 1877, was 4'o&d. per ton of coal worked. And during the same year, at a colliery in Northumberland, using Norway, the cost was The following books may be consulted: Templeton's " Workshop Companion " ; Laslett's " Timber and Timber Trees"; Rattray and Mills' " Forestry and Forest Products." EXPLOSIVES. General rule 12 of the Mines Act, 1887, deals with explosives. The chief points are as follows : No explosive may be taken into the mine except in cartridges in a canister containing not more than 5lbs. Charging tools of iron or steel are forbidden, and coal may not be used for tamping. No explosive may be pressed into an in- sufficient hole. A charge may not be unrammed, and no hole may be bored for a charge at less than six inches from a hole where the charge has missed fire. In any place where a safety lamp is required, or which is dry and dusty, shots may only be fired by a person appointed for the purpose, who must first examine all places within 20 yards. If gas has been reported a shot may not be fired unless there is not sufficient gas at or near the place of firing to render it unsafe ; or unless the explosive be of such a nature that it cannot fire gas. If the place be dry and dusty a shot may not be fired unless the place to a distance of 20 yards be watered; or, should watering damage the roof or floor, unless the explosive be of such a nature that it cannot inflame gas or dust. If the place be dry and dusty and be on, or contiguous to, a main haulage road, a shot may not be fired unless both the last - mentioned conditions have been observed ; or else such one of them as may be applicable, and also all workmen have been re- moved from the seam and from all seams communicating with the shaft upon the same level, except the shot firers and such others not exceeding ten as are necessarily employed in attending to furnaces, machinery, signals, horses and inspection. The Explosives Act, 1875, is too long to abstract ; but a few points may be mentioned. No explosive may be kept for sale without a licence. Not more than 20 Ibs. of gun- powder, and 150 Ibs. of safety cartridges (as ordinary shots) or 15 Ibs. of any other explosive, or in lieu of any less amount of gunpowder not so kept, half that amount of other explosive may be kept for private use without a licence. Cartridges for blasting may not be made in a private house; they must be bought ready made, or manufactured in a EXPLOSIVES ACT. 29 workshop in connection with, but detached from, (25 to 100 yards) the store. The store must not be situated in a mine or quarry where persons are employed ; or within a certain distance (the exact distance depending upon the quantity of explosive for which it is licensed ; but 200 yards is the maximum, and should houses, etc., be subsequently built within the prescribed zone, the store must be removed), of houses, workshops, railways, roads, fires, etc. It must be substantially built of brick, stone, or concrete ; or be ex- cavated in solid rock, earth, or mine refuse not liable to ignition ; and so made and closed as to prevent unauthorised persons from having access. There must be no exposed iron, steel, or grit in the building. Nothing may be kept in the store but the explosive and the necessary implements, which must be made of copper, wood, or brass. Lightning conductor required, unless the store be underground or licensed for less than 1,000 Ibs. of gunpowder. No person under 16 to enter, except under supervision of a grown-up person. The quantity of gunpowder that may be kept varies from 300 to 4,000 Ibs., according to the character of the store. If licensed for mixed explosives, 300 to 4,000 Ibs. of powder, and, in addition, 1,500 to 20,000 Ibs. of safety cartridges (the cases are included in the weight) ; in lieu of each Ib. of powder, J Ib. of any other explosive may be kept ; and, in addition to each Ib. of powder, 5 Ibs. of safety fuzes. A copy of the rules must be affixed to the store. There are several common sense regulations, such as no smoking allowed, etc. See " Guide Book to the Explosives Act," by Major Majendie. All explosives exert an equal force in every direction. An explosive takes effect along the line of least resistance. In a homogeneous material this will be the shortest line from the charge to the face, and will be most efficient when at right angles to the shot-hole, and least efficient when it coincides with the axis of the shot-hole. The quantity required varies as the cube of the line of least resistance. A cartridge, one inch diameter, and 38 inches long, contains one Ib. of powder. The chemical changes that take place when powder is fired, may be roughly represented as follows : EXPLOSIVES. (45-) S + 3 C Gunpowder fires at about 482 Fahr. and expands to at least 1,500 times its original volume. (Miller's " Inorganic Chem. 5 ') TABLE X. EXPLOSIVE. COMPOSITION. Heat Evolved Vol. of Gas per Ib. Product indicating Blasting Effect. Gunpowder. Nitro- glycerine. Dynamite.* ( Potassium Nitrate 74*7 < Sulphur 12 "45 1,093 2,372 1,780 3'6l II'4I 8-56 3,945 27,064 15,236 ( Charcoal . 12*25 /C H O 3(NO ) .. 1 /Nitro- glycerine 75 \ \ Silica 25 / (Proc. I.C.E., XLIII.) Tons of coal got in 1875 perlb. of powder employed both in hewing and stone work Northumberland Steam Coal Northumberland House, Coking Coal, &c Durham House and Gas Coal Durham Coking Coal, &c. Cumberland . 5'95 25-80 2 I '00 23-99 21-42 Whole district . 9-97 (J. B. Atkinson.) In Pennsylvania in 1881 and 1882, 2-23 tons only; but the seams lie at high angles, and there is much stone work. Substitutes for Explosives. The wedge, wedge and feather, Macdermott's multiple wedge and feather, Macdermott's screw wedge, Macnab's * Dynamite, if used with water tamping, will get coal in good condi- tion ; and has this advantage over gunpowder used with water tamping, that a blown out shot will not fire gas. (See Report of Accidents in Mines Commission, 1886.) LIME CARTRIDGES. 31 hydraulic cartridge, the Haswell Mechanical Coal-getter, the Seaton Delaval Detacher, and many others. See Trans. N.E.I., ii., xii., xiv., xix., xxiii., xxxiii. Lime Cartridges. Quick lime + water in excess = slaked lime + steam. (46.) CaO + H 2 O + Aq = CaH 2 O 2 + Aq. Mountain limestone is calcined, ground to a fine powder, and formed into cartridges 2\ inches diameter, with .a groove along the side by means of an hydraulic pressure of forty tons. The shot-holes being drilled, an iron tube half-an-inch in diameter, having a small external groove on the upper side, and provided with perforations, is inserted along the whole length of the bore-hole. This tube is enclosed in a bag of calico, covering the perforations at one end, and has a tap at the other. The cartridges are then inserted and tamped. A force pump is connected with the tap by means of a flexible pipe and water, equal in bulk to the quantity of lime used, is forced in. The water being driven to the far end of the shot hole through the tube, escapes along the groove, and through the perforations and the calico, flowing towards the tamping into the lime and driving out the air before it. The tap is then closed. The pressure of steam generated by the usual charge of seven cartridges is 2,850 Ibs., and the expansion of the cartridge about five times its original size. The advantages claimed for this system are : Absolute immunity from explosion of gas, there being no fire or flame. There is no smoke or noxious smell. The roof is not shaken, and the coals in falling produce less dust. Skilled labour is unnecessary, and the coal can be got with much less exertion than by wedging. Major Paget Mosley. Trans. Midland Inst. of Mining, Civil, and Mechanical Engineers. Vol. VIIL, pp. 8793. It has been averred that the heat given off is sufficient to ignite gas, but Abel says that the maximum heat produced by the slaking of the lime is 700 degrees, whereas it takes a temperature of 2,000 degrees to ignite gas. On the other hand, coal dust ignites at a temperature much below 700 degrees Fah. MACHINERY. Nature and Uses of Machinery. The use of machinery is to transmit and modify motion and force. In the action of a machine, the three following things take place : ist. Some natural source of energy com- municates motion and forte to a part of the mechanism called the prime mover. 2nd. The motion and force are transmitted from the prime mover through the train of mechanism to the working piece ; and, during that transmission, the motion and force are modified in amount and in direction, so as to be rendered suitable for the purpose to which they are applied ; and 3rd, The working piece, by means of its motion, or of its motion and force combined, accomplishes some useful purpose. (Rankine, M.M., p. i.) Some of these terms require explanation, viz. : Force may be defined as an action between two bodies, causing or tending to cause, rest or motion. The British unit of force is the force required to support a weight of one Ib. at London, or roughly, at any other place on the globe. Work may be defined as the combination of force and motion. The unit of work is a force of one Ib. exerted through a distance of one foot. Power may be defined as the speed of doing work. The unit of power is a force of one Ib. exerted through a distance of one foot in one minute. A horse-power is equal to 33,000 of the above units of power. It is sometimes convenient to use the second, or the hour as the unit of time instead of the minute. One British horse power then is: 550 foot Ibs. per second ^33,000 foot Ibs. per minute= 1,980,000 foot Ibs. per hour. ENERGY. 33 We have then the following rules : (47.) Units of Work= Force in Ibs. x Distance in feet. Force in Ibs. x Distance in feet. ( 4 8.)UmtsofPower=- Time in minutes . Force in Ibs. x Distance in feet. (40.) Units of Horse-power =-TF : : : lime in minutes x 33,000. Energy may be denned as the power of doing work. Heat is a form of energy. The unit of heat (or thermal unit) is, approximately, the quantity of heat required to raise one Ib. of water one degree Fahr. Different bodies require very different quantities of heat to effect in them the same change of temperature, and the quantity of heat that one Ib. of a body requires to raise its temperature one degree is called the specific heat of that body. TABLE XI. SPECIFIC HEATS. Air 0*2379^ Carbonic Acid o *2 1 64 Carbonic Oxide 0*2479 Vapour of Water ...0*4750 Nitrogen 0*2440 Sul. Hydrogen 0-2423 Hydrogen 3'446 After-damp o -268 Oxygen 0*2182 0-1686 3 0-1763 | 0-3640 ,0-1727 3 ' I8 33 rt 2*4046 |j 0*196 Water ............... 1*0000 Cast Iron ......... 0-12983 Wrought Iron ...0*11379 Copper ............ 0-09515 Silver ............... 0*05701 Tin .................. 0*05695 Gold ............... 0-03244 Lead ............... 0*03140 Coal ............... 0*2777 Coke ............... 0*20085 Calcium ............ 0*1670 Slaked Lime ...... 0*223 (Regnault.) We have, then, the following rule : The units of heat required to raise a given body, a given number of degrees = the weight of the body x the number of degrees x the specific heat of the body. If, therefore, U= Units of heat. D= Degrees Fahr. the body is heated. S= Specific heat of body. (See Table XI.) W=Weight of body in Ibs. (50.) U= 34 ENERGY. Connexion between heat and work. One unit of heat= 772 units of work. A Ib. of coal yields about 14,000 units of heat. An engine, therefore, consuming one Ib. of coal per hour, should develop 2^ = 5! horse-power 33,000 x 60 nearly. One Ib. of marsh gas yields about 23,550 units of heat. One Ib. of hydrogen about 62,000. One Ib. of illuminating gas about 22,000. Electricity is a form of energy, and may be converted into heat as in the electric light, or into work as in an electric engine. One Ib. of zinc reacted upon by sulphuric acid in a battery yields 1,018 units of work. Energy is indestructible, but in converting one form of energy into another, there is always practically great waste. For example : One Ib. of coal, though it yields 14,000 units of heat, and should, therefore, give us 5^ horse-power, will only give, in the best steam-engines, about J of one horse- power. The principal sources of energy are ; Food, fuel, heads of water, and the wind. The principal prime movers are ; Men and horses, steam- engines, water-wheels, and wind-mills. The train of mechanism which connects the prime mover with the working piece may consist of wheels, levers, spears, ropes, a fluid, electricity, etc. The working piece may be a bit, pump, cage, tub, etc. We see then that machinery enables us to make use of the energy Nature provides. The following books may be consulted : The Con- servation of Energy, Balfour Stewart; Energy in Nature, Carpenter ; Heat a Mode of Motion, Tyndall. PRIME MOVERS. A. Men and Horses. Food is the source from which men and horses obtain their energy ; their efficiency is very great as compared with the efficiency of a steam-engine, about 27 per cent, of the units of heat yielded by a horse's food being turned into mechanical energy or work, against about 10 per cent, in a steam-engine. Mr. Hunting is the great authority in the North of England on the feeding and management of colliery horses, and his views are embodied in a paper published in the Trans. N.E.I., vol. xxxii. Table XII., extracted from this paper, shews that beans and peas contain the largest pro- TABLE XII. Water. %* |g II Oss -ss 3*p C/3C/3 ii 8>l i Ij 1 S6'5 945 PRESSURE, TEMPERATURE, &c. t OF STEAM. 51 TABLE XVI. continued. Total Pressure. Lbs. Tempera- ture, Fah. Weight in Ozs. per Cubic Foot. Volume compared with Volume of Water that has produced it. Total Units of Heat per Ib. from 32. Latent Heat per Ib. 27 245 I '0928 915 >I57 943 28 247 I 3 I2 883 ,157-5 942 29 249 1696 854 ,158 940 30 251 2080 827 ,159 939 31 253 2 4 8 80 1 ,i59-5 938 32 254 286 767 ,160 ' 936 33 2 5 6 3 2 5 755 ,160-5 935 34 2 5 8 360 734 ,161 934 35 260 400 7i4 ,161-5 933 3 6 26l 438 695 ,162 93 1 37 263 '477 677 ,162-5 93 38 264 515 660 ,163 929 39 266 '553 644 ,163-5 928 4 268 590 628 ,164 927 4i 269 628 614 ,164-5 926 42 271 66 5 600 ,165 925 43 .272 704 587 ,165-5 924 44 273 741 574 ,166 923 45 275 779 562 ,166-5 922 46 276 816 55i , 166-8 921 47 277 853 . 539 ,167 920 48 279 891 529 ,i67-5 919 49 280 928 519 ,167-8 918 50 28l 965 509 ,168 917 5i 283 2'QOI 499 ,168-5 916 52 284 2-038 490 , 168-8 915 53 285 2-075 482 ,169 914 54 286 2'II2 473 ,169-5 913 55 287 2-149 465 ,169-8 912 56 288 2M85 457 ,170 9ii'5 57 290 2-222 45 ,170-5 911 58 291 2-259 443 ,170-^ 910-5 59 292 2-294 436 ,171 910 60 293 2-33I 429 ,171'i 909'5 65 298 2-512 398 ,i73 906 70 303 2-689 372 ,1748 901 75 308 2-867 349 ,176-5 898 80 312 3 '043 329 ,i77-8 895 85 316 3-217 3ii ,179-2 891 90 320 3'390 295 ,180-5 888 95 324 3 '56o 281 ,181-5 885-7 IOO 328 3728 268 ,182-5 883-7 E 2 52 CONDENSATION. Surface condensers. For ordinary colliery engines (i.e., for engines working at pressures of about 40 Ibs. and with very little expansion), for each indicated horse-power, 4 square feet of tube surface are required, and 2^- gallons of cooling water per minute. Injector condensers. To the quantity of water theoreti- cally required about 30 per cent, should be added. Let Q = lbs. of condensing water theoretically required per Ib. of steam to be condensed. H = Total heat of exhaust steam (see Table XVI.). T = Temperature of water of condensation, t = Temperature of condensing water. Then : (77.) Q = ?El The cost of repairs per annum is (roughly), for : An egg-ended boiler, ,13. A Cornish boiler, .17. A Lancashire boiler, 20. If the feed-water be bad the cost will be much higher. Chimneys ; Let H = Height in feet. L = Length of flue and height of chimney in feet. V = Velocity with which the gases travel in the chimney in feet per second. D = Inside dia., if round, or length of side, if square, in feet. h = Head in feet of air, of the temperature of the air inside the chimney, required to produce the draught. T = Absolute temperature of gases discharged by chimney. t = Absolute temperature of air before entering the furnace. Then : CHIMNEYS. 53 (79-) In practice 300 cubic feet of air will be required per Ib. of coal burned ; and the absolute temperature and volume of the discharged gases will be about double the absolute temperature and volume of the air before entering the fur- nace. About 1 6 feet per second is a fair value for V. Authorities. "A Practical Treatise on Heat," Box; "The Mechanical Engineering of Collieries," Percy ; " Pocket-Book of Engineering Formulae," Molesworth ; "Steam Boilers," Armstrong; "The Mines Act, General and Special Rules; The Steam Engine," Rankin; "The Theory of the Steam Engine," Baker; "Steam and the Steam Engine," Clark. Trans. N.E.I., xvii. and xxxii. ; "Tall Chimney Construction," Bancroft ; "The Workshop Companion," Templeton ; " The Steam Engine," Cotterill. TRANSMISSION OF POWER. IT is impossible to place boilers in a mine inbye at long distances from the shaft. The economical transmission of power, therefore, to long distances is a matter of great importance. Wooden spears may be used for distances of 300 or 400 yards, where the road is straight \ but for distances greater than this our choice is confined to compressed air, wire ropes, steam, and, in _ certain cases, water. Some day, possibly. electricity may be used for this purpose. Compressed air. Theory. We note in our practical experience of com- pressors and air engines that : 1. If you compress air (i.e., do work upon it), you will raise its temperature, and the rise in temperature will be an exact measure of the work done upon the air. 2. If you expand air against any opposing force (i.e., get work out of it), you will lower its temperature, and the fall in temperature will be an exact measure of the work got out of the air. 3. If you raise the temperature of air you will increase its expansive force. 4. If you lower the temperature of air you will decrease its expansive force. These phenomena can be easily explained if we assume the truth of the dynamical theory of gases. It is supposed that the particles of air are flying about in all directions; and that, if they were not retained by any force, they would fly apart into infinite space. The particles strike against one another, and against the sides of the vessel that contain them ; and, being perfectly elastic, they rebound with a velocity equal to the velocity of collision. The energy of the particles is the heat that the air possesses. To increase COMPRESSED AIR. 55 the temperature is to increase the energy, ?>., to increase the velocity of movement of the particles. To decrease the temperature is to decrease their velocity. In other words, then, " Heat is a mode of motion." Suppose we have a cylinder full of air and the piston be pushed down. The particles of air striking the piston will rebound from it with their original velocity, plus an increased velocity due to the velocity of the piston. That is to say the advancing piston striking the particles will increase their velocity, which we have just seen is equivalent to an increase of temperature. Conversely if the piston be pushed back again by the expansive force of the air, each particle that strikes the piston gives up a portion of its energy to it, and rebounds with a decreased velocity, i.e., there will be a decrease in the temperature of the air. Changes in the temperature, pressure, and volume of air are governed by the following laws : Let P! V x and T 1 = the initial pressure, volume and abso- lute temperature of a given weight of air. P 2 , V 2 , and T 2 = the final do. do. Then (80.) At constant temperature PiV 1 = P 2 V 2 . V T (81.) At constant pressure J = rT \ 2 2 P T (82.) At constant volume = L. 2 2 If air be expanded or compressed adiabatically, the fol- lowing relations hold good : /Q,X Ps/VAi^oS ?:-*-- The units of work = U, required to compress a volume of air = Vj, to a volume of air = V 2 ; or to compress a volume = V from P to P 56 COMPRESSED AIR. ist, isothermally : i.e., at constant temperature, are : (8 S .)U = P 1 V 1 hyplog.Yi. V 2 2nd, adiabatically : i.e., without loss of the heat due to compression, are : As, when air is compressed adiabatically, the rise in its temperature is an exact measure of the work done upon it ; the units of work required to compress it can be calculated from the rise in temperature. This increase of temperature T 2 Tj is given by (84); and the units of work = this quan- tity x weight of the air in Ibs. x specific heat of air at con- stant volume expressed in foot Ibs., viz. : 130*3. Thus if W = weight of the air in Ibs. : (87.) U = (T 2 -T 1 )i30'3W. Conversely in order to calculate the units of work given out by compressed air when expanded isothermally or adiabatically the same formulae (i.e., 85 to 87) should be used. Practice. In order to compress air a Ram Compressor may be used if there be a plentiful fall of water (" Power of Water," Weale's series, No. 82); or the compressors of Sommeiller, Colladon, &c., described by Andre in his " Mining Machinery," where a fall of water is not available. Loss due to physical properties of air. Cooling of com- pressor with cold water, heating of air-engine with hot water or with steam ; clearance spaces. Loss due to friction in conducting pipes. The formula for calculating this is of the same form for all fluids, and is given on p. 62, formulae (97) to (99). P p. is the loss of pressure between the compressing engine and the air engine, and d is the weight in oz. of a cubic foot of the compressed air, which last may be got from formula (144), bearing in mind that two inches of the barometer are equal to i Ib. of pressure. The greater the pressure of the air the less its efficiency. ROPE TRANSMISSION. 57 Mr. W. Daniell found that, with a pressure of 19 Ibs. above the atmosphere, the compressed air gave 45^8 per cent, of the horse-power of the compressing steam-engine ; with a pressure of 40 Ibs. above the atmosphere, 25*8 per cent. only. The following books may be consulted : " Spon's Diet of Eng. Supp. ;" Trans. N.E.I., xxi., xxii., xxxi. ; "Mining Machinery," Andre; "Power of Water/' Glynnj "Trans- mission of Power by Compressed Air," Zahner. Wire Ropes. Wire rope, or Telodynamic, transmission, is not 'used in England so much as we think it might be; though the confined passages of a mine will not admit of the large sheaves necessary for a perfect installation. HP = Horse power transmitted to driven sheave. S = Speed of rope in feet per minute. P = Force, or pull of rope, in Ibs. K = Coefficient of efficiency depending upon the dimensions of the sheaves, the distance, &c. (88.) HP= KPS . 33,000 Where the main and tail rope system of haulage is in use, the return sheave may be utilised for working a pump or other machinery. It should be cleaded with wood, which can be renewed from time to time. If, however, a special installation has to be made, it will be better to use an endless rope. The driving and driven sheaves should be of large diameter, 200 times that of the rope is found to be the best proportion ; but little more than half this can be attained in mines. They should be cleaded with wood willow is the best gutta-percha, or leather set on edge. The intermediate sheaves may be a foot in diameter, though the larger they can be made the better, up to six feet ; the rope of tough, flexible steel, made of a large number of small wires. With large main sheaves (12 to 15 feet), its speed should be from 30 to 40 miles an hour, and it is under these conditions, viz. : A rope running at a great speed, under a small strain that a rope transmission is 58 ROPE TRANSMISSION. most effective. With the small sheaves (say main sheaves six feet, and intermediate sheaves 12 inches), that can only be used in mines, about 12 miles an hour would be a suit- able speed ; and we know of one transmission, running at only 6 miles an hour, that was fairly successful. The objection to these slow speeds is the great strain upon the rope. Binding sheaves are not required \ but it is conve- nient to have the driving or the driven sheave set upon a sliding carriage to compensate for the stretching of the rope. The loss of power due to friction, &c., in a carefully- proportioned, above-ground transmission, appears to be only about 2 J per cent, and f per cent, in addition for each 1,000 yards. In the mine, however, such perfec- tion cannot be attained on account of the small diameter of the sheaves and rollers, and the numerous curves. For distances of from 2,000 to 3,000 yards, 30 to 40 per cent, of the horse-power of the engine will be absorbed in driving the ropes. Authorities : Proc. I.M.E., 1874, p. 56; Trans. N.E.I., xvii. ; " Transmission of Power by Wire Ropes," Stahl ; " The Engineer," xxiii. and xxxvii. Steam. The losses in a steam transmission are of two kinds, viz. : 1. Loss of steam from condensation. 2. Loss of pressure from friction. The loss of heat, and consequent condensation, is due to two causes radiation and contact with air. Loss by Radiation. Let U = units of heat lost by radiation, per hour. S = surface of covered pipe in square feet. D = difference of temperature in degs. Fahrenheit between surface of covered pipe and drift or shaft sides. R = (see Table XVII.) STEAM TRANSMISSION. 59 Then (89.) U = - Let L = Ibs. of steam condensed per hour. H = latent heat of steam (see Table XVI.) at the mean pressure in the pipe. Then (90.) L = . TABLE XVII. THE RATIO OF HEAT EMITTED OR ABSORBED AT DIFFERENT TEMPERATURES. Let R = ratio of loss of heat. /=cent. temperature drift sides. T = cent. difference of temperature between pipe surface and drift sides. Then (91.) R = I2 47 2 x i 'OQ77 *x (1-0077 T -i) Reduced to Fahrenheit's scale this formula gives the following, Table XVII. : T. t. 59 6 3 K 68 72^ 80 86 9i 95 Degs. R. R. R. R. R. R. R. R. 18 'I2O 14 I6 S 178 22 3 254 271 300 27 14 159 I8 S 190 247 2 7 6 305 327 36 16 177 206 202 272 299 330 352 45 18 20 229 231 297 3 2 3 '357 3 8l 54 20 23 251 26l 323 348 385 406 63 -225 25 2 7 6 289 350 '375 407 1-435 72 25 283 302 317 '377 403 429 1-464 Loss by Contact with Air. This will be greater with horizontal than with vertical pipes. 6o STEAM TRANSMISSION. Horizontal Pipes. Let Uj = units of heat lost per hour by a horizontal pipe from contact with air. S = surface of covered pipe in square feet. R 1 = (see Table XVIII.) D! = difference of temperature in degrees Fahrenheit between surface of covered pipe and the air. A = (see Table XIX.) Then (92.) U^D^AS, And the Ibs. of steam condensed can be found from (90). TABLE XVIII. THE RATIO OF HEAT EMITTED OR ABSORBED BY CONTACT WITH AIR WITH GIVEN DIFFERENCES OF TEMPERATURE. Let Rj = ratio of loss of heat. /= difference of temperature of the pipe surface and the air in degrees cent. Then Reduced to Fahrenheit's scale, this formula gives the following, Table XVIII. of values of R a : t. R,. t. RI. Degrees. Degrees. 9 18 0782 Q'943 8 219 263 27 1-037 72 305 36 1-109 81 34i 45 I-I68 90 372 TABLE XIX. If r radius of horizontal covered pipe in inches, (94.) A = 0-421 0-307 LOSS BY CONDENSATION". 61 r A. r A. r A. r A. 2 Q'5745 3i 0-5154 4^ 0-4892 6* 0*4682 2j 0-5574 3* 0-5087 4l 0-4856 7 0-4648 2i 0-5440 3i 0-5028 5 0-4824 7* 0*4619 2| 0-5326 4 0-4978 |i 0-4768 0'4593 3 0-5230 4i 0-4930 0-4722 9 0-455I Vertical Pipes. Let U n = units of heat lost per hour by a vertical pipe from contact with air. A! = (see Table XX.) Then S > R i> and D i> as in (9 2 )- \xD / ^11 1 1 1 > And the Ibs. of steam condensed can be found from (90.) TABLE XX. If r= radius of vertical covered pipe in inches. h = height of vertical pipe in inches. 7.6 x -2044. W / 1 1 / / / V T"3 ' / T ( T"T"* This formula gives the following Table XX., taking A x in feet. Radius in Inches. Height of Pipe in Feet. 50 100 200 300 r A!. A,. A x . Aj. 2 0-4769 0*4650 0-4571 0-4534 2$ 0-4676 0*4560 0-4478 0-4442 3 0*4614 0-4500 0-4419 0-4384 3i 0-4562 0-4448 0-4368 0-4333 4 0-4526 0-4412 0-4333 0-4299 4i 0-449I 0-4378 0-4300 0-4266 5 0*4462 0-435 2 0-4273 0-4239 5i 0-4437 0-4328 0-4250 0-4216 6 0*4416 ' 0-4298 0-4220 0-4186 6i 0*4398 0-4289 0-4212 0-4178 7 0-4380 0-4272 0-4196 0-4162 z* 0-4366 0-4257 0-4181 0-4147 8 0-4352 0-4244 0-4168 0-4134 9 0-433 0-4220 0-4146 0-4112 62 STEAM TRANSMISSION. By means of the above formulae and tables, the quantity of steam that will be condensed (that is to say, the quantity of steam that must be produced by the boiler in addition to that required to drive the engine,) in the range of pipes can be easily calculated if only the surface tempera- ture of the pipes, of the air, and drift sides be known. How these may be obtained will be presently pointed out. Loss by Friction. The laws governing the resistance that fluids meet with in passing through iron pipes (and other conduits also ; in which, however, we are not now interested) do not appear to be thoroughly Understood. M. Stockalper, however, found, from experiments upon the flow of compressed air through pipes made at the Mont Cenis tunnel, and published in the "Revue Universelle des Mines," Ser. 2, Vol. VII., p. 257, that Darcy's formula for the flow of water through iron pipes, reduced in the ratio of the density of air to that of water, gave satisfactory results. Acting upon these sugges- tions, the author has made use of Darcy's formula for the flow of water, after having converted it into British units, as follows : Let P = boiler pressure in Ibs. per square inch. p = pressure required at engine in Ibs. per square inch. /= length of pipe in yards. d weight of i cubic foot of the fluid in oz. (for steam, see Table XVI.) D = diameter of pipe in inches. Q = cubic feet of the fluid passing per second. (See below.) a = (See Table XXL) Then P p = loss of pressure between boiler and engine ; And _ V97-/ .f I;0 oo,ooo (98.) lad 1,000,000 (P 'p) <99-> Kf d LOSS BY FRICTION. There is some difficulty in finding the value of this quantity Q, the mean volume ; but assuming that, in a pipe of uniform section, with no very great variation in temperature, the condensation takes place uniformly from end to end ; and that the loss from leakage is inappre- ciable : If V = volume of steam in cubic feet per second pro- duced by the boiler. v = volume of steam in cubic feet per second consumed by the engine. Q = mean volume in cubic feet per second, passing through the pipe. Then, assuming that V v is the volume of steam lost by condensation ; that is to say, neglecting leakage : (100.) Q 2 = 6 and formula (97) becomes lad (101.) P-/ = 1,000,000 TABLE XXI. VALUES OF a FOR DIFFERENT INTERNAL DIAMETERS D, OF PIPES IN INCHES. (102.) a = 3o6,703 5 ,494*. and / \ r , '000^0046 (103.) 0= '000507 + _ V-ZZ_ Internal Diameter of Pipe in Inches. a. Internal Diameter of Pipe in Inches. a. I* 2 2* 3i 4 4i 5 91,960 7,302 2,232 812 381 190 1037 597 51 6 6i 1 9 10 ii 36-54 23-29 1 5 '47 10-58 5 '34 2-927 1717 0-9872 6 4 STEAM TRANSMISSION. The Design of a Steam. Transmission. The only difficulty that can arise in making use of these formulae for the purpose of determining the size of pipes and boiler power required for any proposed transmission, lies in the estimation of the surface temperature of the covered pipe. This will depend upon the composition used, and its thickness ; and upon the temperatures of the steam, the air, and drift sides. As it is independent of the diameter and length of the pipe, the simplest plan is to make an experiment by covering three or four yards of pipe with the composition to be used. Or reference may be made to a very valuable series of experiments upon various non-con- ducting compositions, carried out by Mr. Bird, Assoc. Sc., and read before the N. of England Institute. See Vols. XXIX., XXXL, and XXXII. The following, Table XXII., shows the results of some experiments made by the author with Wormald's composi- tion. It will be noted that the differences of temperature do not vary much : TABLE XXII. EXPERIMENTS WITH WORMALD'S COMPOSITION. Thickness of Com- position. Approximate Temperature of the Steam. Temperature of Surface of Covered Pipe. Temperature of the Air. Difference of Columns 3 and 4. Temperature of Drift Sides. Inches. Degrees. Degrees. Degrees. Degrees. Degrees. I| 28l 122 77 45 72 I| 275 101 62 39 62 If 275 100 62 38 62 l 28l 121 77 44 72 Il 7 6 271 1 2O 77 43 72 !is 285 120 79 4i 74 If 287 132^ 9i 44 89 11 287 I 3 2 94 38 93i. If 287 109 77 32 open air Ig 286 107 76 3i do. 2 t 287 107 77 30 do. 2i 286 104 76 28 do. Having determined the temperatures in one or other of these ways, the steam required to supply the condensation PRACTICAL DETAILS. 65 can be readily obtained from formulae (89) to (95). Expe- rience seems to show that a little under 10 per cent, must be added to this for condensation at the steam traps and expansion joints. The volume required for the engine is of course known, and this (the engine volume) added to the condensation volume gives the gross quantity to be supplied by the boiler, and consequently the boiler power required. The mean volume squared passing through the pipe is got from the engine volume and condensation volume by formula (100), and finally the size of the pipes from formula (99) and Table XXI. Practical Details. Provision must be made for carrying off the water of condensation, and for expansion of the steam pipes. The first is well understood, and I would only suggest that a trap be placed as near the boiler as possible, to intercept the water carried over by priming. It was found at Broom- hill that whereas the trap next the boiler gave a gallon per 7 '3 yards of pipe, the second trap from the boiler gave a gallon per 15*8 yards. For the low pressures usually adopted at collieries (say not more than 45 Ibs. above the atmosphere) the ordinary stuffing-box expansion joint answers admirably ; but with higher pressures there is considerable difficulty. The New York Steam Company (pressure 80 Ibs.) have made a great many experiments upon expansion joints, and finally settled upon a modification of the diaphragm joint. It is made of discs of copper 0-04 inches thick, corrugated concentrically, and supported on radial backing plates, which prevent the diaphragm from being distended to rupture by the pressure. Provision must be made for dealing with the exhaust steam. If the engine is used for pumping, and there be sufficient water, the simplest plan is to turn the exhaust direct into the suction pipe. By this means not only is the steam killed but a vacuum is obtained, and the engine made more efficient. At East Howie Colliery, instead of turning the exhaust direct into the suction, they carry the exhaust pipe some thirty yards inside the rising main, and then turn 66 TRANSMISSION OF POWER SUMMARY. it into the suction pipe. By this means they consider that they get a more perfect condensation than if the exhaust steam were turned direct into the suction ; and they cer- tainly pass cold water through the pump instead of hot, which is an undoubted advantage. Authorities : Box on "Heat;" Trans. N.E.I., Vols. XXIX., XXXI., XXXIL, XXXV., and XXXVI. Summary. A compressed air installation requires a large capital ex- penditure : but once established, it is not expensive to maintain where fuel is cheap. It is the most handy form of transmission for mining purposes, as the power can be readily split up by means of branch pipes, and carried in small quantities to numerous points. In addition, the ex- haust air improves the ventilation, cools the mine, and can be used for clearing away gas. A wire rope transmission is much less costly in the first case than compressed air ; and, if properly laid out, a large quantity of power may be led to one or two points with little loss of useful effect. But the cost of maintenance is larger and the power cannot be readily carried in small quantities t ) many points. Steam is not to be recommended, except in special cases ; for, however carefully the pipes may be covered and the exhaust dealt with, there will always be a considerable escape of heat, which is very inconvenient in the confined passages of a mine. Electricity is not likely, we think, ever to compete suc- cessfully with wire ropes or with air for the transmission of power in mines ; where the maximum distance is only about three miles. It will, however, no doubt be applied some day for the transmission of power to very great distances. It is immaterial whether the road be straight or crooked ; whether the work to be done be concentrated, or distributed in small quantities over many points. MAGNETISM AND ELECTRICITY. Practical Electro-Magnetic Units. Electromotive-force (and Potential) : The Volt= io 8 abso- lute units ; and is from 5 to io per cent, less than the E.M.F. of one of Daniell's cell. Resistance: The Ohm = io 9 absolute units ; and is about equal in resistance to 48-5 metres of pure copper wire, i mm. dia., at o cent. Current ; The Ampere = lo" 1 absolute units ; and is that furnished by an E.M.F. of one volt, through a resistance of one ohm. Quantity: The Coulomb = icr 1 absolute units; and is the quantity of electricity passing per sec. across any section of a circuit through which a current of one ampere is flowing, i.e., one Ampere = one Coulomb per second. Capacity: The Farad = io~ 9 absolute units; and is the capacity of a conductor which a charge of one coulomb raises to a potential of one volt. To calculate the Horse-power of a current : Let HP = Horse-power. A = Amperes. V = Volts. Then: One Ampere volt = one Watt. .-. one Horse-power = 746 Watts. Compass Surveying. It must be remembered that the needle does not point to true north ; but. in Great Britain, at the present time, to the west of true north : and that the angle contained by these F 2 68 MAGNETISM AND ELECTRICITY. two straight lines ; viz., the true north and south line, and the magnetic north and south line, differs at different places. This angle, at any place, is called the declination or, more commonly, the variation of the needle for that place. The variation is the same along a straight line drawn through the North of England coal-field, skirting the W. side of Durham, and the E. side of Newcastle. At the present time, the magnetic variation on this line is 19 29' W. of N. At col- lieries in this coal-field E. and W. of this line, the maximum difference is 15'; viz., 15' less on the E., 15' more on the W. The variation is decreasing at the rate of about 7' a year, so that, in 1890, the variation along the above line will be 19 29' - (7' x 3) =19 29'- 2i'=i9 8' W. of N. TABLE XXIII. PLAN EQUIVALENTS. Inches per Inch, i.e., Scale. Feet per Inch. Yards per Inch. Chains per Inch. Miles per Inch. A cres per Square Inch. Inches per Mile. 792 66-0 22 'O I'D 0-0125 O'lO 80'0 1,584 132-0 44 -o 2*O 0-0250 0-40 4O-O 2,376 198-0 66-0 3'0 0-0375 0-90 26-66 2,500 208-33 69-44 3*15 0-039 0-996 25344 3,168 264-0 88-0 4*o 0-05 I -60 20 -o 3,96o 330-0 IIO'O 5'o 0-0625 2-50 16-00 7,920 660-0 220-0 10 -o 0-125 IO'O 8-0 10,560 890-0 296-66 13-33 0-166 1777 6-0 63,360 5,280 1,760 80-0 I'O 640-0 I "O 126,720 10,560 3,5 2 160*0 2-0 2,560 o'5 190,080 16,840 5,280 240-0 3 -0 5,760 o-333 253,440 2I,I2O 7,040 320-0 4-0 10,240 0-25 Firing Shots The advantages of Electric Shot Firing are : Shots fired simultaneously thereby more effective. Saving of time. Safer, because not fired until all men are out of the way ; and should a shot miss, it cannot fire afterwards in the face of the workman examining it. SIGNALLING AND LIGHTING. 69 Two kinds of fuse are used, viz. : (i.) Tension fuse fired by a frictional, or magnetic-electric machine. (2.) Quantity fuse fired by a voltaic battery. (See " Practical Treatise on Coal Mining," by Andre, p. 208.) Signalling. The Single-wire System, in which signals can only be sent from certain fixed stations. The Double-wire System, in which signals can be sent from any point, by making contact between the two wires. In both these systems, the electric current is made to ring a bell ; and a convenient form of battery is the Leclanche, as it does not require much attention, and is not liable to speedy exhaustion. Lighting. The Incandescent Lamps of Maxim, Swan, &c., are used* both for lighting at bank and below ground. These are stationary lights, and the current is produced by a dynamo- electric machine, driven by any convenient water, or steam- engine, with which dynamo the lamps are connected by means of wires. No moveable lamp has yet been used in mines, as there is a difficulty about the battery. Mr. Swan, however, is engaged upon this problem and has invented a portable miners' electric lamp ; but, as at present con- structed, it is too costly for practical use. One great advan- tage of the incandescent lamps, is that, burning only in a vacuum, they cannot (if reasonable precautions are taken to prevent breakage of wires) fire gas. In an installation of 50 lamps and upwards, each lamp of 20 candles, one horse-power is required per 8 to 10 lamps. Swan's 2o-candle lamps, joined in series, require an E.M.F. of 45 to 60 volts per lamp, with a current of one ampere. Joined parallel, they require a current of one ampere per lamp, with an E.M.F. of from 45 to 60 volts. Geissler Tubes, as in the lamp of Benoit and Dumas, have been suggested ; but the lamp is heavy, and the light small. 70 MAGNETISM AND ELECTRICITY. Transmission of Power. A little has been done in France in this direction. The efficiency of electricity compared favourably with the alter- native, compressed air. (See Trans. N.E.I., xxxi., Abs., pp. 9 n, xxxii. Abs., pp. 13, 14, xxxiii. Abs., p. 71, and xxxiv.) Fire-Damp Detectors. Liveing, Ansell, Maurice, Swan, and Somzee have each contrived an electric fire-damp detector. That of Liveing seems the most practical, and is in regular use at Pagebank and other collieries. They are all described in the Trans. N.E.I. Danger. From shocks, there is none when a continuous current of not more than 200 volts, or an alternating current of not more than 75 is used. This is, I believe, the limit adopted by the Board of Trade, and errs slightly on the right side. From sparks firing gas, should any be present, must always be guarded against. This may occur at the commutator ; or from a broken wire, the spark leaping across the space be- tween the two ends at the moment of rupture. The following books may be consulted : " Electricity and Magnetism," Silvanus Thompson ; " Electricity," John T. Sprague ; Trans. N.E.I., Vols. xxx., xxxi., arid xxxvi. SEARCH FOR MINERALS. , * , ( Irregular. ( i. Lying at high angles by costeaning. ( Regular. < ( 2. Lying at low angles by boring. 1. Costeaning: A simple process requiring no machi- nery. 2. Boring: Theoretically, borings, of one or more holes, should give us the following information, viz. : One hole : Vertical distance from the surface to the deposit; thickness of the deposit ; quality of the deposit. Three holes : (In addition to the above) amount of dip ; direction of dip. To find the amount and direction of dip of a bed, by means of three bore-holes. Let A, B, and C, be the three bore-holes. S = Angle of dip of bed. V = Angle between the strike of the bed and AB. a = Distance from A to B. a' = Do. A to C. W = Angle in a horizontal plane between AB and AC. d = Difference of the depths of A and B. d' = Do. A and C. In both cases starting from the same horizontal plane. (io6.)TanV = a- d 72 BORING. Borings are made : By hand, a jet of water, Mather and Platfs process , the Diamond Process. Hand-boring; The head-gear, rods (wood, iron, steel, ropes), and tools (cutting, clearing, extracting). The Diamond Process. The engine, quill, rods, sediment tube, core tube, crown, split-ring, and core. Iron rods weigh about 21 Ibs. per square inch of section per fathom; and iSJlbs. per square inch of section per fathom in water. Cost of boring. For average coal measure rocks, 'js. 6d. per fathom for the first five fathoms ; 1 5 j. per fathom for the second five fathoms ; 225-. 6d. per fathom for the third five fathoms and so on, has been a standard price in the north for many years. A Scotch borer in 1883 advertised his price at 4$., in the place of 75. 6d., as above. The price for diamond boring is 6s. per foot for the first 100 feet ; i2s. per foot for the second 100 feet; iSs. for the third, and so on. To find the cost of a bore-hole Let c = cost. a = price for first step. d = increase in price for each additional step in depth. n = number of steps. ( } n (107.) c= I 2a + (n- i) d >- When n is not a multiple of a, this rule is only approxi- mately correct. The following deep bore-holes may be mentioned : At Schladebach, Leipzic, 956 fathoms, nin. dia. at the top and 1*22 in. at the bottom ; it begins in the Trias, and passes through the Permian into the Devonian formation, which point was reached in the summer of 1886. Sperenberg, Berlin, 695 J fathoms, 12 in. dia., all in rock salt excepting the first 47^ fathoms. Creusot, by Kind, 503 fathoms. The Rochefort bore-hole, 469 fathoms in Triassic beds. The Mondorf bore-hole, Luxemburg, 400 fathoms. The New BORING. 73 Saltzwerk bore-hole, Westphalia, 380 fathoms. And the Sub-Wealden bore-hole, near Battle in Sussex, 31 yf fathoms. The following books may be consulted : " Mining Ma- chinery," Andre ; " Mine Engineering," Greenwell ; Trans. N.E.I., Vols. ii., x., xiii., &c. ; and "Lectures on Mining," Gallon. SINKING. Mines Act, &c. Prohibition of single shafts, sees. 16, 17 and 18. Fencing abandoned mines, sec. 37. Fencing and securing shafts, inspection, &c. General Rules, 18 to 38. Pits may be sunk by means of : (i.) Men and machinery placed at the bottom of the pit. (2.) Men and machinery situated at bank. (1.) Workmen in the Pit. The ordinary method adopted in the North of England is fully detailed in the works of Andre and Greenwell. The workmen, standing upon the bottom of the pit, blast out the rock, and send the excavated material to the surface by means of an engine, rope, and kibble. The sides of the shaft are retained first by temporary cribs and backing deals, and afterwards by a permanent walling. The feeders of water are drawn to the surface in the kibble or pumped by a set hanging in the shaft, and are finally tubbed back, one after the other, as they are met with. This system is all that can be desired under ordinary circumstances. Herr Poetschs freezing method: See " Colliery Guardian," Nov. 1 6th and 23rd, 1883. May be adopted where the feeders are too excessive for the ordinary method and the ground too loose for the Kind-Chaudron process. (2.) Workmen at Bank. The Kind-Chaudron method : The barrack, the engine, the rocking-lever, the spears, the free-fall, the trepan, the whimble, the tubbing, the moss box, and the concrete back- ing. The cost is very variable, from ^74 to ^338 per fathom having occurred in actual practice. Warington-Smyth sums up an account of this method as follows : KIND- CHA UDRON. 75 1. A very hazardous operation has been converted into a comparative certainty. 2. An economy of 50 to 75 per cent, has been effected on the outlay, as compared with the ordinary system carried out in the same districts. This immense gain arises mainly from : a. No pumps or pumping engines being required b. The prevention, in a great degree, by the pressure of the water in the shaft, of irruptions of quicksand. c. The employment of a comparatively small number of men, and these being, for the most part, workmen of a less highly-paid order than the regular sinkers. d. The suppression of the vertical joints of the tubbing, whereby leakage, costs of wedging, and tendency to dis- placement, are avoided. 3. Risk to life is, to a great extent, eliminated by the whole of the work being done at the surface. 4. Damage to the buildings and wells of the neighbour- hood is prevented by the process not requiring the drawing of water and sand. (Trans. N.E.I., xx., 198.) The Chavette method for sinking through running sands. See Trans. N.E.I., xxxii., Abs. p. 51. Chaudron's rule for thickness of tubbing is : Let E = Thickness in metres (i m. = 39'37 inches). R = Radius of shaft in metres. P Pressure in kilogrammes per square centimetre (100 metres of water weigh 10 kilogrammes per square centimetre.) pp (108.) E = '02+ 500 See formula (42). Shaft Fittings. Walling ; This is made of bricks, fire-clay lumps, stone, or concrete. For strength see formula (42). Tubbing : To keep back water, of cast-iron in segments or rings. 76 SINKING. Brattice ; Now that each colliery must have two shafts, permanent brattice is not much used. The Countess shaft, Whitehaven, is divided into four compartments by a masonry brattice; the courses are 10 inches thick and arched, so that each is self-supporting. Guides ; These are made of wood, iron rods, iron or steel rails, or of wire ropes. Wire ropes are, perhaps, the best, on the whole, as they take up very little room in the shaft, and admit of the cage being run with great velocity. Water rings ; Keeps ; Rappers : Wire with lever, speak- ing-tube, or electric. Shaft-gates ; and water rings are also required. The Cost of sinking and fitting up a shaft by the ordinary method depends, to some extent, upon the diameter and depth of the shaft, the rate of wages and materials ; but much more upon the strata met with and the quantity of water. Some items of the cost for a 14 feet pit, 100 fathoms deep, sunk through ordinary coal measure strata and with little water, would be about : Total labour cost of sinking and walling 2$ per fathom; Contractor for sinking, including small stores ;i4 per fathom. Making walling beds, 6 each; Walling with fire-clay lumps, ^15 per fathom walled ; Tubbing, with cast-iron segments, ^90 per fathom tubbed; Plank brattice 2 los. per fathom; Guides of wood, i$s. per fathom; Iron or steel rail guides, 50 Ibs. per yard, 2 los. per fathom; Wire rope guides, i $s. per fathom. And the total cost for the finished pit about ^50 per fathom. If there is a good deal of water (but still not more than can be easily mastered by the ordinary method of sinking) this price might be doubled. Shaft Pillars, &c. If D = Depth of shaft in fathoms. S = Size of shaf^pillars in yards. (109.) S= A/ x 22 is an approximate rule. The 5 exact size must depend upon the special circumstances of each case. THE UNIVERSITY )) DEPTH OF SHAFTS. .77 JJ ^'fr If W - Width of shaft in feet. H = Height of hanging on place in feet. L = Length in feet of longest prop, rail, &c., that can be taken down into the mine. Some Deep Mines. The deepest shaft in the world is I believe, that of a lead mine, the Adalbert shaft, Prizbram, 572 fathoms, 1884 (the Maria shaft, Prizbram is also about the same depth) ; and the deepest mine, the Viviers Reunis coal mine, at Gilly, near Charleroi, 581 '5 fathoms; the depth of the shaft is 570 fathoms, but there is a staple at the bottom, n^ fathoms deep. The deepest mine in England is the Ashton Moss colliery, near Manchester, sunk to the Black mine, 472*5 fathoms (the total depth of the shaft is 475 fathoms). The seams dip 9" per yard, so that parts of the workings are about 500 fathoms (1886). There are also Rosebridge colliery, Wigan, sunk to the Arley mine, 403 fathoms (the total depth of the shaft is 407-! fathoms) ; Dolcoath tin mine, Cornwall, 404 fathoms (1884); Harris Navigation colliery, S. Wales, 373J fathoms to the p-feet seam (total depth of shaft, 380 fathoms) ; and Uukinfield colliery, Manchester, sunk to the Black mine, 358^ fathoms. The deepest mines in the North of England are Seaham colliery, 301 fathoms to the Busty seam; Silksworth colliery, 290 fathoms to the Hutton seam ; and Monkwearmouth colliery, 287! fathoms to Hutton seam. Underground Temperature. The temperature of the earth increases as we descend ; but at what rate is not exactly known. In round numbers, the temperature at 100 feet is constant, and is equal to the mean annual temperature of the place. Below this point, the temperature increases i Fahr. for each 56 feet. The mean annual temperature of Newcastle is 49 Fahr. The temperature in the deeper parts of the workings at Ashton Moss is from 86 to 90. 78 IMPORTANT ADITS. In some of the Comstock lode silver mines, Nevada, workings are being carried on at a depth of 336 fathoms (1877), and at a temperature up to 123, the rock having a pretty uniform temperature of 130. This great heat is due to the hot springs, some of which have a temperature of 158 Fahr. Chemical decomposition is thought to be, in part, at any rate, the cause of this high temperature. Important Adits. Gwennap, Cornwall, drains 30 square miles, is 40 miles long, including branches, and varies in depth from 30 to 90 fathoms. Ernst August, Harz, 14 miles long, including branches; greatest depth, 222 fathoms, gradient i in 2,000. The Blackett level, from Allendale town to the mines at Allenheads, 7 miles, of which 4| are completed ; gradient i in 660. The following books may be consulted: " Mine Engineer- ing," by Greenwell ; " Practical Treatise on Coal Mining," by Andre'; Trans. N.E.I., xx., xxxi. ; " Lectures on Mining," by Gallon ; "Alines, Miners, and Mining Indus., U.S.," by Drinker; "American Jour., Sci. and Arts," 3 ser., xvii. ; "Mec. Eng. of Collieries," by Percy ; Report of Coal Com., 1871; Proc. I.C.E., vols. Ixiv., Ixxi. ; and "Underground Temperatures," by Prestwich. SYSTEM OF WOKKING. The method to be adopted depends upon a great variety of circumstances, such as the mineral worked, its mode of occurrence, &c., &c. Minerals are found as Seams or Lodes (regular deposits). As Impregnations or Masses (irregular deposits). Deposits vary much in thickness ; confining ourselves only to those that are being, or have .been worked, we find : Coal : The Chapelet seam at the Hasard colliery, Liege, i \ feet; the Three-quarter, Midgeholme, Northumberland, from 22 to 30 inches; the Maudlin, Ryhope, Durham, 1 2 feet ; the Ten-yard seam, Dudley, upwards of 30 feet in places ; the great seam, Beraudiere, St. Etienne, up to 82 feet ; the great seam at Be'zenet up to 200 feet. Salt .-Cheshire, 75 to loofeet; Wieliczka, in Galicia, 100 feet; Middlesborough, up to 90 feet; Sperenberg, Berlin, 3,890 feet. Iron-ore ; Lord Leconsfield's mine, Cleator-moor, Cum- berland, 60 feet; the Lias band, Eston, 18 feet. Silver lodes of Schemnitz, Hungary, 30 feet. Alum Shales on the Meuse, 90 feet. Slate Mines in the Ardennes, 60 feet. Various as are the conditions of occurrence of mineral deposits, the systems of working them may be all classed under one or other of five heads, viz. : Above Ground : Pumping (Salt, Middlesborough). Washing (Gold, California). Quarrying. 8o BORD AND PILLAR AND LONG WALL. Under Ground: Bord and Pillar. Long Wall. We are not interested here in the first three. Bord and Pillar may be defined as any system of mining in which the deposit is removed in two or more workings. A portion of the deposit being left during the first working or workings in order to support the roof and sides of the excavation. (Post and Stall, Stoop and Room, Pillar and Breast are synonymous with Bord and Pillar.) Long Wall may be defined as any system of mining in which the whole of the deposit (or, in the case of very thick deposits, a horizontal slice of it) is removed in one working; no portion being left to support the roof and sides of the excavation. The Long Wall and Bord and Pillar methods, as adopted in the North of England for the working of seams of coal, may be shortly described and compared as follows : Long Wall and Bord and Pillar. In Long Wall, a face of considerable width, say 100 to 500 yards, is opened out, and the coal is worked along the whole distance either in one lift or in steps. The roads main-gates and cross-gates, as they are called pass through the goaf and are supported on packs built up of the stone taken down to form height in the roads. The roof along the face is also supported on packs made from the refuse i.e., the band or foiling of the seam, and where this fails, on timber which is drawn and shifted forwards as the face advances. All superfluous stone, &c., not required for the packs, is cast back into the goaf, and one of the main elements of success in this system of working is that there should be sufficient of this to fill, more or less completely, the void left by the abstraction of the seam, so as to let down the roof evenly and gradually. In Bord and Pillar the seam is first cut up into rectangular masses by two sets of excavations, driven at right angles to one another, and then these masses are removed in slices BORD AND PILLAR AND LONG WALL. 81 about four to seven yards wide. The first operation is called working in the " Whole Mine," and the second working in the " Broken." Long Wall then may be defined as any system of working in which the seam is removed at one operation : Bord and Pillar as any system in which the seam is removed by two or more series of workings. The Bord and Pillar and Long Wall systems of working are adapted to different circumstances, so that an exact comparison is impossible, though a general one may be made as follows : 1. Ventilation. In Long Wall the air enters by the main gate, and dividing into two splits, passes along the face, returning by roads on the extreme right and left. Nothing can be simpler than this arrangement ; very little brattice is required, and the air, having the shortest possible distance to travel, acquires the least possible heat from the strata, a matter of great importance in deep mines, and also requires the least possible ventilating pressure (i.e., less expenditure of money) to set it in motion. In Bord and Pillar the air also enters by the central drift or Mother-gate bord, and divides into two splits ; but, as the air has to be taken into each bord, it has a very much longer distance to travel, and a great deal of brattice is required. On the other hand, should there be much gas, it can be isolated to the bord in which it is being given off in Bord and Pillar ; whilst in Long Wall it will foul the whole face on the inbye side. 2. Produce. In Long Wall all the seam may be extracted, and whilst the weight of the roof helps to break down the coal at the face, it does not rest upon it long enough to crush the coal. This, combined with the small amount (if any at all) of nicking and narrow work, tends to the produc- tion of the maximum of round coal. In Bord and Pillar all the seam cannot be extracted, as some coal must always be left in stooks, and in addition, a portion of the pillars is often lost by falls of roof. In the whole workings, small is produced by nicking and narrow work and often in the broken by crush. The result being 82 BORD AND PILLAR AND LONG WALL. a smaller production both of unscreened and of round coal than in the Long Wall method of working. 3. Cost. In Long Wall the cost of putting, supervision, and materials (i.e. t rails, sleepers, and brattice) will be less than in Bord and Pillar because the distance is shorter; and, as there is no yard work, and the weight of the roof helps to bring down the coal, the cost of hewing also will be less. On the other hand, shift and stone work will be very expensive ; so much so, that where powder cannot be used, Long Wall is, in many cases, inadmissible. A given length of face will stow more men in Long Wall than in Bord and Pillar. 4. Surface Damage. When it is intended to work out the whole of the seam less damage is done by Long Wall than by Bord and Pillar, because the space formerly occupied by the seam is filled up by the stowage, and though this cannot be done so completely as to support the weight of the superincumbent strata without considerable compression of the stowage, yet the character of the support is the same over the whole area, and the surface is let down gradually and uniformly. In Bord and Pillar the surface damage usually takes the form of irregular depressions dotted about here and there, putting a stop to all farm drainage. 5. Accidents. Accidents from falls of stone are less likely to happen in Long Wall than in the broken workings of Bord and Pillar ; and, as no coal is left below ground, under ground fires, from the spontaneous combustion of small coal crushed and ground together by falls of roof, are impossible. On the other hand, gas cannot be isolated to the place where it is being given off, as in Bord and Pillar. And in Long Wall, the men being closer together, should an explosion occur, more are likely to be killed. Summary. Long Wall is suitable for thin seams (less than four feet) or very thick (more than twelve feet) seams, lying at any angle ; especially when they produce sufficient refuse for stowage and contain no gas and few troubles. Bord and Pillar is suitable for seams of moderate thick- ness (from 3! to 8 feet) lying at low angles : especially if there be gas and troubles. STOPING. 83 Stoping. In the mining of metalliferous veins a Bord and Pillar system is adopted which is called stoping. It may be shortly described as follows : The vein having been cut up by means of levels and winzes into pillars, 25 to 50 yards in length by 15 to 30 yards in height, is worked by one or other of two methods, viz. : 1. By overhand stoping. 2. By underhand stoping. 1. Overhand stoping. A jud is worked off (the full width of the vein and by 5 6 feet in height) starting from one of the lower corners of a pillar and carried right across the pillar horizontally from winze to winze. This jud, having gone 4 or 5 yards, is followed by another jud immediately above it ; this is followed by a third, and so on. So that the portion of a pillar, still unworked, looks like a staircase, beneath which the miners stand ; and the portion worked, which is stowed up with the deads, looks like a staircase upon which (or sometimes upon timbering) the miners stand. The useful mineral is separated from the deads and passed down from step to step, until it reaches the rolley- way below. Or else passages are left for it in the stowage down to the rolley-way level, with a sliding shutter in their lower ends by means of which the tubs are filled. 2. Underhand stoping. A jud is worked off, beginning at the upper corner of a pillar, and carried right across horizontally from winze to winze. When this jud has gone a few yards, a second is set away immediately below it, and so on, so that the unworked portion of the pillar is like a staircase, upon the steps of which the workmen stand. The useful mineral is separated from the deads and passes down the staircase from step to step, until it reaches the rolley- way level. The deads are stowed away on timber above the miners' heads. Comparison of the two methods. The ore is broken down more cheaply by overhand than by underhand stoping ; the leading of the useful mineral down the spouts is cheaper than passing it down the steps ; and the stowage of the deads is more easily accomplished. The consumption of G 2 84 STOPING. timber depends, perhaps, more upon the circumstances of the lode than upon the system adopted ; but, as a rule, less will be required for overhand than for underhand stoping. The roof of unworked ore in overhand stoping, except when it is of a very friable nature, will be safer than the stowage roof in underhand stoping. On the other hand, if the mineral be of a very valuable character portions of it may be lost in the stowage on its passage down the spouts or down the steps of stowage. Shortly. Overhand stoping is the most generally appli- cable. Underhand stoping more costly from the expense of timbering, the greater difficulty of breaking the ore, of stowing the goaf, and leading away the useful mineral is suited for those mines where the great value of the mineral makes the loss of a small quantity a matter of great import- ance, and for those where the ore is so friable as to make a dangerous roof for the working places. It is adopted in some German, a few English, and many South American mines. Cost of Working. This is very variable, depending upon the price of labour and the nature of the deposit. In the case of coal, about one half of the labour cost is due to hewing, one-third to other underground labour, and the remaining one-sixth to surface labour. To this must be added materials, rents, rates, fuel, agency, depreciation, and interest on capital. In all, perhaps, about $s. per ton on unscreened coal into waggons at the pit, in ordinary condi- tions of trade. Collins in his book, referred to below, gives some costs of labour in metal mines. The following books may be consulted: "Metal Mining," Collins; "Metalliferous Minerals and Mining/' Davies; " Ore Deposits," J. A. Phillips; Trans. N.E.L, vi. and vii. ; and the books on Mining already mentioned. WINDING. Winding Engines. The work to be done is not continuous for more than a few seconds, and is variable in amount, being greatest at the lift when the whole weight of the rope and the inertia of the mass set in motion have to be overcome. The weight of the rope is counterbalanced, as see below. The resistance due to the inertia of the load may be found by the following rule : Let R = Resistance in Ibs. W = Weight of load in Ibs. V = Maximum velocity in feet per second g = Force of gravity = 32. T = Time in seconds taken to acquire the velocity V. / x T> _WV (See "Practical Mechanics," by Twis- -7r den, p. 231.) The friction of the guides has to be overcome. In designing a Winding engine to do any given work, consult the " Mechanical Engineering of Collieries," by Percy. Counterbalances. The common form in the north is the chain and staple. See the description of the Silksworth counterbalance. Trans. N.E.I., xxy. 201. The Incline Counterbalance was adopted at Killingworth Colliery. F = Counterbalancing force in Ibs. for a short distance on any portion of the incline. W = Weight of counterbalance in Ibs. H = Height of the portion of the incline in feet. L = Length do. do. 86 COUNTERBALANCES. The Pendulum Counterbalance is used at Dudley Colliery. F = Conterbalancing force in Ibs. in any position of the pendulum. W = Weight in Ibs. of the counterbalance. A = Angle the pendulum makes with the horizontal. COS The Tail Rope Counterbalance as used at Garswood Colliery, near Wigan, consists of a rope of the same size as the winding rope. It passes round a pulley at the bottom of the shaft, and has one end fastened to the bottom of one cage, the other end to the bottom of the other cage. The Koepe system does away with the winding drum altogether, and substitutes a sheave connected with the engine at bank. There is a return sheave at the bottom of the shaft. Two ropes are used, one connected with the tops of the cages and passing round the sheave at bank ; the other connected with the bottoms of the cages, and passing round the sheave in the sump. The Conical Drum, as used at Boldon the full cage at the bottom of the shaft being attached to the small diameter of the cone, the empty cage at the top of the shaft being attached to the large diameter of the cone. Automatic Variable Expansion is sometimes employed. Drums. Cylindrical, vertical (flat rope), or conical. Pulley-Frames. The principal strains are in two directions, viz., one vertical, due to the weight of the load ; the other more or less horizontal, due to the pull of the engine. Timber, iron, and masonry will bear a crushing strain better than a tensile strain, or breaking across. In constructing pulley frames, therefore, the materials should be so placed as to be subjected to a crushing strain. This may be done in more WINDING PULLEYS, &c. 87 than one way ; but, in practice, it is found most convenient to employ two main struts, one vertical, parallel with the vertical portion of the rope; the other, more or less horizontal, parallel with the horizontal part of the rope. In order to fix the size of long timber struts, see formula (41). Pulleys. The following rule is given for the diameter of round iron or steel rope pulleys, viz. : Rope, i in. cir., requires pulley 10 ft. diameter. 1 1 in. 10 J ft. ij in. ii ft. if in. i lift. and so on. In order to save the ropes, the pulleys are sometimes set on springs, as at Cambois Colliery. Let F = Force in Ibs. applied at rim of pulley required to overcome friction of axle. W = Weight upon pulley axle in Ibs. D = Dia. of pulley in inches. d = Dia. of axle in inches. m = Coef. of friction (say 0-07). (1.4.) F- Ropes, Chains, Cages. Ropes are either round, flat, or tapering, and are made of hemp, aloes, iron, or steel. For deep pits, round, steel ropes, are most in favour. For the strength of pit ropes, see formulae (i to 21). Chains should be annealed occasionally, otherwise they become brittle, and are likely to snap. The general rule in the north is to anneal cage chains once a month ; annealing too often, decreases their tensile strength. For strength of chains see formula (22). Cages are made of iron or steel, have from one to four decks, and carry from one to eight tubs. An iron cage TO FIND MEETINGS. weighs about f of its load of full tubs ; a steel cage about - of its load. Sundries. Detaching hooks. See Trans. N.E.I., xxix., 201. Safety cages are not much used in the north. To find meetings, &c., with flat ropes. Let n = Half the number of revolutions. d = Distance of meetings from bottom of pit in inches. r = Radius of drum at lift in inches + t. t = Thickness of rope in inches. (115.) d = 3*i4i6n (2r + n it). Let D = Depth of pit in inches, n = Number of revolutions, r = Radius of drum at lift in inches + \ t. t = Thickness of rope in inches. it.) (117.) r ^ D -(n (n 2 x 3'i4i6n The following books may be consulted : Andre, Green- well, and Percy, already mentioned ; Trans., N.E.I., xxv. DRAINING. Pumps, &c. The Lifting Pump has the engine situated at bank. Advantages and disadvantages of, viz. : The engine is easily got at for repairs, engine cannot be drowned up, pumps can be carried down to a great depth, working parts even when drowned easily brought to bank for repairs. On the other hand : First cost very large, working cost large, take up much room in shaft. The Forcing Pump may have its engine either at bank or in the mine. Advantages and disadvantages of, viz. : First, when engine at bank : The engine is easily got at for repairs, engine cannot be drowned, pumps can be carried down to a great depth, the spears balance the column of water. On the other hand : First cost very large, working cost large, take up much room in shaft when more than one rising main required, and, if the working parts are drowned, they cannot be brought to bank for repairs. Second, when engine in pit : First cost is small, working cost small, take up little room in shaft. On the other hand : Danger of engine being drowned, engine not so easily got at for repairs, difficult to make joints in the rising main, and to make clacks to stand the pressure at a great depth. The Syphon is used for bringing water over a ridge from a higher to a lower level. The short leg must not have a vertical length of more than 34 feet, i.e., the ridge over which the water is to be lifted must not be more than 34 feet. (The greatest height of ridge in practice depends upon the special circumstances of each case.) The long leg need not have a vertical length of more than 34 feet. The effective pressure, expressed in feet of water column, is equal to the vertical length of the long leg in feet (not more than 34 feet), less the vertical length of the short leg in feet. 90 DRAINING. The Shaft. i st. The water tub can be used where the quantity is small ; but, in some cases, large quantities have been raised in this way. 2nd. The Winding engine pump is a pump attached to the winding engine, usually at night; but, sometimes, whilst coal is being drawn. 3rd. The Lifting engine is situated at bank, and may be either a Beam engine, or Rotative engine. 4th. The Forcing engine may be situated at bank and may be a Cornish engine, a Bull engine, a Rotative engine ; or it may be situated in the mine, and be Direct-acting or Rotative. The Workings. i st. Occurrence of feeders. The coal-field is basin-shaped, and formed of alternate layers of permeable and imper- meable strata. Water, entering at the outcrop, will run through the first until intercepted by faults, fissures, pumping shafts, &c. In the North of England Coal-field shallow pits wet ; deep pits dry. When sinking, therefore, the feeders should be tubbed back in succession, as soon as they are encountered. 2nd. Water levels and under level drifts. -This is the best way of dealing with water, when possible. 3rd. Raising water from the dip by means of The water- tub, the hand-pump, or horse-pump, when the units of work are not very great. The tail-rope pump, steam-engine, and spears, steam-engine and rope, compressed air, and elec- tricity, when the units of work are large. Syphons, hydrau- lic engines and water-wheels, may be used in some special cases. In dealing with constant feeders by men or horses : find the units of power by multiplying the Ibs. of water per minute by the vertical distance in feet and add 5o/ for friction. Then : i man will be required per 900 units of power, i horse 6,000 The man (or horse) will not of course work continuously DRAINING. 91 for 24 hours per day ; but if he works, say for 8 hours, /. F sin a | m cos a (F + E) + m'S -1- sin a (E + R) I TT But sin a = and cos a practically = i. Therefore L (136.) P=__ |m(F + E) + m'S + : 2TW~ F -(E + R) - Self-acting inclines are suitable for straight roads rising inbye one inch to the yard and upwards. COST OF HAULAGE. 99 4th. The main and tail-rope system is suited for a narrow plane, having a regular gradient, and several branches. 5th. Endless chain or rope is suited for wide straight undulating planes, without any branches. The gradient, &c., may be calculated from formulae (136) to (138). 6th. The main rope system is used on planes dipping inbye one inch to the yard and upwards. The weight of the empty set has to overcome the friction of the empty set, the rollers, sheave, and rope. P = E sin a (m cos a E + m'S + m'R), and we get 2 LW (140.) T= yth. Compressed air-engines, stationary and locomotive. Hydraulic engines and electric motors are also used. A tub will hold about 50 Ibs. of unscreened coal per cubic foot. The exact quantity depends of course upon the specific gravity of the coal ; but also upon the size of tub and the proportion of round coal, the larger the tub and the greater the percentage of round the greater the weight per cubic foot that it will hold. The cost of haulage is very variable, depending upon the gradients, the length of road, and quantity led. Excluding interest on capital, the cost per ton of coal conveyed one mile is about : \d., ordinary railroad with locomotives. 6d. y ordinary road with horses, excluding maintenance of road. ^d. (?), canal with horses, excluding maintenance of canal. Canal with steam-tugs in some cases as low as T ^o^., excluding maintenance of canal. H 2 loo HAULAGE. IT^-, level railroad with horses. 2j^., underground level rolley-way with horses. 2^., ordinary underground rolley-way, rope or chain haulage. If the quantity be small, the rolley-way be level or dipping slightly in favour of the load, and about half-a-mile or under in length, horses can compete favourably with mechanical haulage. But with large quantities, steep gradients, and long distances, mechanical haulage is cheapest. The following books may be consulted : Books by Andre', Gallon, Greenwell, already mentioned. Trans. N.E.I., iii. and xvii. The use of steam for canal-boat propulsion, Man- chester Assoc. of Eng., Jan. 1886 ; Proc. I.C.E. xxxi. GENERAL PROPERTIES OF AIR AND GASES. Air and gases may be defined as elastic fluids in contra- distinction from liquids which are inelastic fluids. The elasticity of the air is used to determine the venti- lating pressure in a mine by means of the water-gauge. Air and gases are ponderable, that is to say, they have weight ; but the weight of a given volume depends upon its pressure and temperature. Pressure : The weight of a given volume of any gas varies as the pressure. In order to find the pressure of the air, we use the barometer. The standard atmospheric pressure at 32 Fahr. and sea- level = 29-922 in. mer. = 14-696 Ibs. per sq. in. = 2,116 Ibs. per sq. ft. = 26,213 ft- f homogeneous air column = 33*9 ft. of water column. To reduce a barometer reading at any point above sea- level to the corresponding reading at sea-level, the following approximate rule is given by Mattieu Williams in " Science in Short Chapters " : To the observed reading add 0*1" for each : 85 ft. up to 510 ft. that the point is above sea-level. 90 ft. from 510 to 1140 ft 95 ft. from 1140 to 1900 ft. 100 ft. when above 1900 ft. Thus 28" at a point 2000 ft. above sea-level = 30-2 * at sea- level. Correction for temperature : Mercury expands about o-oooi of its volume for each degree Fahr. To reduce, therefore, a reading at any temperature to the corresponding reading at the standard temperature of 32, subtract To^Wo of the observed height for each degree above 32 ; or, if the temperature be below 32, add y^Wo f r eacn degree. 102 THE BAROMETER. Depth of pits : If R = Reading of barometer at lower station. r= at higher T = Temperature Fahr. at lower station. t= at higher H = Difference of level in feet. (142.) H = 56,300 (Log. R-Log. r) ( i + -~ J T + t 56,300 (i+i* \ 90 More simply : /R r\ / T + t (143.) H = 49l ooo - R- r /49> 000 (900 * T + 1) + 900 H \ \ 49,000 (900 + T + t) 900 H J Very roughly, the mercury rises i inch for each 150 fathoms of depth. Temperature : The weight of a given volume of any gas varies inversely as its absolute temperature. Absolute temperature = 459 + Fahr. temp. To find the weight of a given volume of any gas at any known temperature and pressure, 459 cub. ft. of air at o Fahr. and bar. i in. weigh 1*3253 Ibs. Therefore, if V = Volume of air in cub. ft. W = Weight in Ibs. I = Barometer in ins. t = Temperature Fahr. To find the weight of any other gas, multiply the weight of air by the specific gravity of the gas. See p. 104. Gas in goaves. It has been estimated that the air-space in a goaf is equal to about one-sixth of the volume of the coal extracted. THE OCCLUDED GASES 103 Absorption of gases by liquids and solids as of air by I water in a pump. Gases enclosed in the pores of coal must be distinguished from the gases that enter into the chemical composition of coal. Sundry analyses of these enclosed, or occluded gases as they are called, are given in the following table : TABLE XXIV. GASES ENCLOSED IN THE PORES OF COAL AND EVOLVED IN VACUO AT 212 FAHR. Name of Colliery. Quality. C0 2 . 0. CH 4 . N. Quan- tity CC per 100 Grams. Cubic Feet per Ton. Navigation Dunraven Cyfarthfa Steam do. do. 13-21 5 '46 iS'QO 0-49 0-44 I'O2 81-64 84-22 67*47 4-66 9-88 I2'6l 250 218 147 90 78 C2 Bute do. Q'2Z O'34 86-Q2 V4Q 37 c 13"? Bonville's / Court \ \Vatney's Anth- racite do 2-62 I4'72 93-13 84-18 4^5 I'lO 555 600 I 99 216 Plymouth Iron/ Works \ Cwm Clydach... Bettwys Bitum- inous, do. do. 36-42 5-44 22'l6 0'80 1-05 O'OQ 6376 2-68 6278 2975 6Q'O7 55'9 55*i 24 "O 20 19-8 8 '6 (Thomas. ) Experiments of Mr. Lindsay Wood on the pressure of gases enclosed in coal. (See Trans. N.E.I., xxx.) The greatest pressure obtained was at Boldon, 461 Ibs. per square inch. TABLE XXV. Transpiration of Gases. That is to say, the passage of gases through minute tubes, such as the pores of coal. 104 DIFFUSION. Name of Gas. Times for Trans- piration of equal Volumes. Velocities of Transpiration. Oxveen (O) I'OOO I 'OOO Air O'QO^O IO74 Nitrogen (N) . . . 0-8768 '141 Carbonic Oxide (CO) Carbonic Acid (CO 2 ) 0-8737 o'7^oo 145 370 Marsh Gas (CH ) O'CCio 815 Ethylene (C 2 HJ O'^O^I 980 Hydrogen (H) 0*4.^70 2-288 (Graham.) Practical bearing. Gases flow from green coal into work- ings. Blowers. Gases assist hewer by breaking down coal. The Diffusion of Gases. When two gaseous bodies are mixed together they gra- dually diffuse themselves through each other so that, after sufficient time has elapsed for the purpose, whatever may have been their relative densities, they are found intimately blended ; the heavier gas does not fall to the bottom, nor does the lighter one rise to the top. TABLE XXVI. RELATIVE VELOCITY OF DIFFUSION. S P g. ^Spg. I ^siiT Velocity of Dif- fusion, Air being taken as unity. Air I 'OOO I 'OOO I 'OOO I 'OOO Hydrogen (H) 0*06926 0*2632 3-7704. r8-? Marsh Gas (CHJ Steam (H 2 O) 0-559 O'621Z 0-7476 0*780.6 i '3375 i '2664 i '344 Carbonic Oxide (CO) ... Nitrogen (N) Ethylene (C 2 H ) " V*J3 0-9678 0-9713 0*078 0-9837 0-9856 0-0880 1-0165 1*0147 I *OI 12 i -0149 1-0143 i "0191 Oxygen (O) I "1056 J-QCIC O'QCIO 0*9487 Sulphuretted Hydro- \ een (H S) f 1-1912 1-0914 0-9I62 0'95 Carbonic Acid (CO a ) ... 1-529 1-2365 0-8087 0-812 (Graham. ) FIRE-DAMP ANALYSES. 105 The above table shows that fire-damp mixes with air more readily than stythe does ; and fire-damp, therefore, is more easily cleared away by the ventilating current than stythe is. TABLE XXVII. FIRE-DAMP ANALYSES. Name of Colliery. CH 4 . N. O. C0 3 . H. Wallsend, from pipe \ on surface j 92-8 6-9 O'O 0-3 O'O lOO'O Jarrow, Bensham Seam 8 3 -I 14-2 0-6 2'I O'O lOO'O Hebburn, Do 86-0 12-3 O'O 17 O'O 100 '0 Jarrow, Low Main Seam 797 I4'3 3-0 2'0 0-3 99 '3 Jarrow, 5/4 Seam 93 '4 4 '9 O'O 17 O'O lOO'O Oakwellgate, Do 98-2 i '3 O'O 0'5 O'O lOO'O Hebburn, Coal 24 ft. \ below Bensham ... / 927 6-4 O'O 0'9 O'O lOO'O (De La Beche and Lyon Playfair.) Authorities : " Coal, Mine Gases, and Ventilation," by Thomas. Trans. N.E.I., xxx. Ganot's " Elementary Physics." " Practical Treatise on Gases met with in Coal Mines/' by Atkinson. "Practical Treatise on Heat," by Box. CHEMISTRY. Compounds and Elements. Substances may be divided into three classes. (i.) Chemical compounds those substances which can be split up by chemical processes into two or more different materials. (2.) Chemical elements or simple substances those which have hitherto resisted all attempts to split them up into two or more different materials. There are at present about 63 of these bodies. (3.) Mechanical mixtures substances formed from a mixture of the above. Atoms. The atomic theory has been adopted to explain the fact, that in chemical combinations elements unite in fixed pro- portions. An atom is the smallest particle of an element that can enter into chemical combination with other elements. Atoms are incapable of being divided. The atoms of the same substance are similar to one another and equal in weight. The atoms of different substances differ in weight. The weight of the atom of hydrogen being taken as the unit ; the atom of oxygen weighs 16, the atom of nitrogen 14, and so on. Chemical Symbols. The atoms of the elements are represented by symbols ; the first letter of the name being generally taken to express the atom. Thus, the atom of Oxygen is denoted by O. Nitrogen N. Hydrogen H, etc. CHEMICAL SYMBOLS. 107 These symbols represent definite weights of the respective elements. H represents the unit of atomic weight, i.e., the weight of the hydrogen atom, whatever that may be. O represents a weight of Oxygen = 16 Hydrogen atoms. N Nitrogen =14 C Carbon =12 The symbols and atomic weights of the elements we are interested in are given in the following table : TABLE XXVIII. SYMBOLS AND ATOMIC WEIGHTS. Name of Element. Symbol. Atomic Weight. Oxygen o 16 Hydrogen H i Nitrogen N 14 Carbon . . . c 12 Sulphur s 32 Phosphorus p 31 Chlorine Cl oC'f Potassium K T.Q Sodium Na 21 Calcium Ca 4O Manganese Mn cir Magnesium Mg 24 Iron F! 56 Zinc Zn 6% Molecules and Formulae. The group of atoms forming the smallest particle of a compound which can exist in a free state, is called its mole- cule ; and the molecule of a compound is expressed by putting together the symbols of the atoms which compose it. This group of symbols is called a formula. Thus the molecule of water contains one atom of oxygen, and two atoms of hydrogen, and may, therefore, be expressed by the formula HHO. When, however, several similar atoms are present, the symbol is only written once, and a small io8 CHEMICAL EQUATIONS. number is put on the right of it, and a little below, to show how many atoms are present. Thus the formula for the molecule of water is H 2 O. When more than one molecule has to be represented a number is placed on the left and level. Thus four molecules of water are represented by 4.H 2 O. The molecule of many of the elements consists of two atoms. Chemical Equations. Chemical changes are represented by equations. Thus, Zn + H 2 SO 4 =H 2 + ZnSO 4 signifies that 65 parts by weight of zinc reacting on 98 parts by weight of sulphuric acid, form 2 parts by weight of hydrogen and 161 parts by weight of zinc sulphate. Equal volumes of all gases contain, under the same con- ditions, the same number of molecules ; equations, there- fore, representing changes in which gases take part, may be read off at once in volumes. If the volume occupied by one atom of Hydrogen be taken as unity, one molecule of each of the gases will occupy two such volumes. Thus : may be read : Two volumes of marsh gas and four volumes of oxygen, form two volumes of carbonic acid gas and four volumes of vapour of water. The following books may be consulted : " Inorganic Chemistry," W. A. Miller ; " Exercises in Practical Chemis- try," Harcourt and Madan; "The New Chemistry." Inter- national Science Series. THE GASES. Oxygen. Symbol, O ; atomic weight, 16. i,ooocubicfeetat32Fahr. and bar. 30 in. weigh 89 -342^5. Oxygen forms by weight f of water, i of the atmosphere, and J of the solid crust of the earth. It was discovered by Priestley in 1774; and has neither colour, taste nor smell. Oxygen is occasionally found amongst the occluded gases ; but principally occurs in mines as a constituent of air. It is essential to life ; but, undiluted, it is not fit to be breathed for more than a short time. It supports combustion, and substances which burn in air burn fiercely in oxygen. It may be prepared from a mixture of potassium chlorate four parts and manganese dioxide one part, mixed together and heated. The whole of the oxygen contained in the potassium chlorate is given off, and a compound of potassium and chlorine remains. Potassium Potassium Chlorate = Chloride (145.) 2KC10 3 =2KC1 + 3 2 . The manganese dioxide is unaltered ; in fact, the oxygen could be obtained from potassium chlorate alone ; but it is found in practice that the presence of manganese dioxide materially assists the operation. Carbonic Oxide. Formula, CO ; molecular weight, 28. 1,000 cubic feet at 32 Fahr. and bar. 30 in. weigh 78-305 Ibs. This gas is the result of imperfect combustion. When a body containing carbon is burnt in air, each atom of carbon will combine with two atoms of oxygen to form carbonic I io HYDROGEN. acid gas ; but, if there is not sufficient air to provide two atoms of oxygen for each atom of carbon, that is to say, if the combustion of the carbon is incomplete, carbonic oxide is formed. It has been detected in rare cases amongst the occluded gases ; and is also produced by the combustion of coke, charcoal, and gunpowder ; and must, in many cases, be one of the constituents of after-damp. It has neither colour, taste, nor smell, but is exceedingly poisonous ; \ per cent in the air, if breathed for long, pro- ducing fatal results. It does not support combustion, but itself burns with a blue flame, forming CO 2 . It may be prepared from hydrogen oxalate, treated with hydrogen sulphate. Carbonic oxide and carbonic acid are driven off, the latter of which is removed by passing the mixture through a solution of potassium hydrate ; but, as this gas is very poisonous, it is best not meddled with by unskilled persons. Hydrogen Hydrogen _ Carbonic , Carbonic Water Hydrogen Oxalate "" Sulphate ~ Oxide Acid * Sulphate. (146.) H 2 C 2 4 + H 2 S0 4 = CO + C0 2 + H 8 + *H a s61 Hydrogen. Symbol, H ; atomic weight, i. 1,000 cubicfeet at 32 Fahr. and bar. 30 in. weigh 5*5832 Ibs. Hydrogen has neither colour, taste, nor smell. It is very inflammable, burning with an almost colourless flame. If breathed in its undiluted state, it quickly causes a very disagreeable sensation ; but this is due to the exclusion of oxygen from the lungs, and not to the properties of hydrogen, which is not poisonous, and may be breathed when diluted with ten times its volume of air, for a considerable time, without experiencing any ill effect. The experiments of Meyer and Thomas show that, in an explosion of marsh gas and air, the whole of the marsh gas is broken up ; and, if there be too little air to form carbonic acid gas and water, carbonic oxide and hydrogen are formed. It may be prepared by treating zinc with hydrogen sul- HYDROGEN SULPHIDE AND NITROGEN. in phate. The hydrogen is driven off, and zinc sulphate is left behind. Zinc + e = Hydrogen + Zinc Sulphate. (147.) Zn-f H 2 SO 4 H 2 + ZnSO 4 . Combined with carbon in the proportion of 4 parts by weight of hydrogen to 12 of carbon, it forms marsh gas, the principal constituent of fire-damp. Hydrogen Sulphide. Formula, H 2 S ; molecular weight, 34. 1,000 cubic feet at 32 Fahr. and bar. 30 in. weigh 94*92^5. Hydrogen sulphide, or sulphuretted hydrogen as it is more generally called, is a colourless- gas, but has a strong smell not unlike that of rotten eggs. It is " generated in small quantity in coal mines, more especially in old-worked por- tions, which are partly filled with water. By the action of oxygen dissolved in water, sulphates are formed ; props in undergoing decomposition in water break up the sulphate of lime and assimilate its oxygen, the sulphur seizing probably the hydrogen of the wood to form hydrogen sulphide." (Thomas's " Coal, Mine Gases, and Ventilation," p. 204.) It does not support combustion, but is itself inflammable, forming water and sulphurous anhydride (H 2 O + SO 2 ). Breathed in an undiluted state, it is fatal to life ; and, when diluted with ten times its volume of air, it produces sickness, giddiness, weakness, and loss of sensation. This gas may be prepared from proto-sulphide of iron treated with dilute hydrogen chloride. Hydrogen sulphide will be given off, and iron chloride formed. Iron Proto Hydrogen _ Iron Hydrogen Sulphide Chloride "Chloride Sulphide. (148.) FeS + 2HC1 = FeCl a + H 2 S. Nitrogen. Symbol, N ; atomic weight, 14. 1,000 cubic feet at 3 2 Fahr. and bar. 30 in. weigh 78*175^8. Nitrogen has neither colour, taste, nor smell, and is in- capable of supporting combustion or animal life, but is not 112 CARBONIC ACID GAS. poisonous, causing death when breathed only by excluding oxygen from the lungs. It is found in large quantities amongst the gases occluded in some coals ; but occurs prin- cipally in mines as a constituent of air. Mixed with oxygen, it forms air, and the readiest way of obtaining it for experiment is to withdraw the oxygen by the action of some substance which has an affinity for oxygen and not for nitrogen. Phosphorus is convenient for this purpose, since it readily combines with oxygen; and the compound formed, phosphorus pentoxide (P 2 O 5 ), is soluble in water, and is, therefore, quickly absorbed when the ex- periment is made over the pneumatic trough, leaving the nitrogen nearly pure. Carbonic Acid Gas. Formula, CO 2 ; molecular weight, 44. 1,000 cubic feet at 3 2 Fahr. and bar. 30 in. weigh 1 2 8 '45 Ibs. Carbonic acid gas has neither colour nor smell, but an acid taste. It is found in large quantities amongst the gases occluded in some coals ; but is also produced in mines by the respiration of men and animals, by the burning of candles and lamps, and by the oxidation of the coal and other substances. It extinguishes lights, and is fatal to animal life. It may be prepared by the decomposition of marble by hydrogen chloride. Carbonic acid gas is given off, calcium . chloride and water are formed in the vessel. -ui , Hydrogen Carbonic , Calcium Marble + ^J^ = AcidGas + Chloride + (149.) CaC0 3 + 2HC1 = C0 2 + CaCl 2 + , A , Water. H 2 O Fire-Damp. Marsh gas. Formula, CH 4 ; molecular weight, 16. 1,000 cubic feet at 32 Fahr. and bar. 30 in. weigh 45 -2 2 Ibs. Fire-damp is a mixture of several gases, its principal con- stituent being marsh gas, CH 4 ; but its composition varies at different collieries, as see p. 105 ; and, in addition to these gases, coal-dust is often present. It is only found in mines as an occluded gas. Marsh gas may be prepared by heating a mixture of sodic FIRE-DAMP. acetate and sodic hydrate in an iron tube. Marsh gas is driven off and sodic carbonate is formed in the tube. Sodic Sodic Sodic Marsh Acetate Hydrate Carbonate Gas. (150.) NaC 2 H 3 O 2 + NaHO = Na 2 CO 3 + CH 4 . For making experiments, ordinary coal gas may be used, though it differs in composition from average specimens of fire-damp. TABLE XXIX. COMPOSITION OF FIRE-DAMP AND COAL GAS. r CH 4 . H. CO. C0 3 . C a H 4 . N. 1 Fire-damp... 1 Coal Gas ... 94 -o 42-0 O 42*0 O 4'5 I'O O 9-0 5' 2'5 1 The exact effects of fire-damp upon combustion ana animal life depend upon its composition, temperature, and density j but, speaking generally, at ordinary temperatures and pressures, when mixed with 3-5 times its volume of air, it does not explode, but burns quietly ; with 5 '5 volumes of air, it explodes slightly ; and with about 9 \ volumes of air the explosion is the greatest. With 13 volumes of air, it explodes feebly ; with 30 volumes of air, it will show plainly on the lamp ; with 50 volumes of air, it can just be detected on the lamp by a skilful observer. If breathed in an un- diluted state, it would soon cause death ; but, mixed with twice its own volume of air, it may be breathed for some time without ill effects. An explosion of marsh gas and air by volume. (1) Suppose we have of CH 4 2 volumes. (2) C requires O 2 = 2 volumes of oxygen forming 2- volumes of CO 2 . H 4 also requires O 2 =2 volumes of oxygen forming 4 volumes of H 2 O. 114 EXPLOSION OF FIRE-DAMP WITH AIR. (3) CH 4 .\ requires 4 volumes of oxygen. But i volume of air contains '21 volumes of oxygen. .'.19 volumes of air will be required for 4 volumes of oxygen. V. 19 volumes of air are required for 2 volumes of CH 4 . .'. 9J volumes of air are required for i volume of CH 4 . And the composition of the after-damp is i volume CO 2 + 2 volumes H 2 O (steam) + 7 \ volumes N. In practice, the exact composition of the after-damp will depend upon the composition of the explosive mixture. In every case the whole of the marsh gas will be broken up and if there be insufficient oxygen to consume all the marsh gas and coal dust, if the last be present some car- bonic oxide and hydrogen will be formed. In all proba- bility, carbonic oxide is formed in the majority of explosions in mines. (Thomas's " Coal, Mine Gases, and Ventilation," P- 323-) The force developed by an explosion of marsh gas and air depends upon a multitude of circumstances, many of which cannot be determined in the case of an explosion in a mine. But in the case of a mixture of marsh gas and air in the most explosive proportions, and enclosed in a strong vessel, we can calculate the force developed, as follows : i Ib. of CH 4 burning to CO 2 and H 2 O yields about 23,550 units of heat. (See p. 34.) Let the initial temperature be 62 Fahr. = 521 absolute. i Ib. CH 4 =i2 oz. C + 40Z. H. 12 oz. + 32 oz. Q = 275 Ibs. CO 2 . 4 oz. H -I- 32 oz. O = 2-25 Ibs. H 2 O. And 64 oz. O are contained in about 1 7 Ibs. air. We have then, taking specific heat at constant volume. (See p. 33.) CO 2 275 x '1711 = "470 units of heat to raise 275 Ibs. CO 2 one deg. H 2 O 2-25 x -364 = '819 do. 2-25 Ibs. H 2 O one deg. N 13*00 x 'i727 = 2'245 do. 13-00 Ibs. N one deg. 18-00 3-534 18-00 FORCE OF AN EXPLOSION. Then the degrees the mixture will be raised are 3'534 = 6663 Fahr. and the volume it will seek to attain = -= 13-8, i.e. } the steady pressure due to the explo- sion = 13-8 atmospheres ; but to this must be added a con- siderably increased force due to shock, the amount of which cannot be calculated. When it is remembered that 13*8 atmospheres are equal to 30,000 Ibs. per sq. ft., whereas the force of a hurricane moving at the rate of 100- miles an hour is only 50 Ibs. per sq. ft., some idea of the terrific force of an explosion may be realised. At the Haswell Explosion, in 1844, Faraday and Lyell drew attention to the part that coal dust might play in an explosion ; but, though the question has cropped up from time to time since, it is only recently that the matter has been thoroughly investigated. Mr. Galloway has, within the last few years, proved that an explosion may be caused with coal dust and air, without the presence of any gas. (See Trans. Royal Soc. 18761884, and "Nature," 6th Nov., 1884.) And it is now admitted that many of the most violent explosions of recent years were due in part, if not entirely, to coal dust. (See " Explosions in Coal Mines," by Atkinson.) The detection of fire-damp is usually effected with the Davy lamp ; but, since it has been shown by Sir Frederick Abel that, if coal dust be present, 1*5 of gas in the air will render the mixture explosive, a more delicate test is required. The following detectors are described in the Trans. N.E.I., viz. : Ansell's, vol. xv. ; Steavenson's, vol. xxvi. ; Liveing's vol. xxvii. ; Forbe's, vol. xxix. ; and Maurice's, vol. xxxvi. Chatellier has introduced a lamp with screen and two shields for the same purpose. Methods of dealing with Fire-damp. Removal by : Firing, now no longer practised. Drainage of goaves by pipes to the upcast (see Faraday and Lyell's report on the Haswell Explosion), or by bore-holes to the surface; both impracticable. Drainage of whole coal by I 2 ii6 THE SAFETY LAMP. bore-holes and gas drifts in a higher seam might answer in certain cases. Dilution with air. (See General Rules i.) Absence of heat : Heat is required for light and for shot- firing. The steel mill of Spedding about 1740. Reflected light, and fish-skins have been tried. The safety lamp due to Clanny, 1811 ; Davy and Stephen- son, 1815. The safety of the lamp depends upon the fact that metal gauze permits air and light to pass but not flame. The conducting power of the gauze is impaired by over- heating, broken wires, dirt, or exposure to a current of gas. The maximum of safety, combined with the maximum of light, is obtained from gauze with wires -g 1 ^ to V in. dia., and spaced with 28 apertures to the linear inch. The best-known lamps are the Davy, Geordie, Clanny, Mueseler, Tin-can, and Marsaut lamps. The Accidents in Mines Commission (1886) report most favourably of the following : Gray's, Marsaut's, the Bon- neted Mueseler, and Evan Thomas's modification of the bonneted Clanny. Swan's portable electric miners' lamp gives a good and perfectly safe light ; but it is too costly for practical use, and will not indicate the presence of carbonic acid gas.* In the Author's opinion, too much attention is paid to securing lamps from the action of violent currents to which they are very unlikely ever to be exposed ; whilst their illuminating power, a daily necessity, is too much neglected. Inventors appear to forget the importance of a good light all round, including the roof. About 42% of the fatal accidents in mines are due to falls of roof and sides, as against 24/ o due to explosions, and a very small proportion of these last have been traced to the safety-lamp. Shot-firing has already been dealt with under the head of explosives. Ambulance Classes. The St. John's Ambulance Association have established classes at many colliery villages, with excellent results. The * It is described, together with the fire-damp detector attached, in Trans. N.E.I, xxxv. AMBULANCE. 117 following are short and clear instructions for the recovery of persons suffocated in mines. Asphyxia. Miners are exposed to asphyxia when the circulation of the air is not sufficiently active, when the mine exhales a quantity of deleterious gas, when they imprudently pene- trate into ancient and abandoned workings, and when there is an explosion. . The symptoms of asphyxia are sudden cessation of the respiration, of the pulsations of the heart, and of the action of the senses ; the countenance is swollen, and marked with reddish spots, the eyes are protruded, the features are distorted, and the face is often livid, &c. The best and first remedy to employ, and in which the greatest confidence ought to be placed, is the renewal of the air necessary for respiration. In succession : 1. Promptly withdraw the asphyxiated person from the deleterious place, and expose him to pure air. 2. Loosen the clothes round the neck and chest ; and dash cold water in the face and on the chest. 3. Attempts should be made to irritate the pituitary membrane with the feathered end of a quill, which should be gently moved in the nostrils of the insensible person, or to stimulate it, with a bottle of volatile alkali placed under the nose. 4. Keep up the warmth of the body, and apply mustard plasters over the heart and round the ankles. 5. If these means fail to produce respiration Dr. Sylves- ter's method of producing artificial respiration should be tried, as follows : Place the patient on the back on a flat surface inclined a little upwards from the feet ; raise and support the head and shoulders on a small firm cushion or folded article of dress placed under the shoulder-blades. Draw forward the patient's tongue and keep it projecting beyond the lips ; an elastic band over the tongue and under the chin will answer this purpose, or a piece of string or tape may be tied round ii8 ASPHYXIA, them, or by raising the lower jaw the teeth may be made to retain the tongue in that position. Remove all tight cloth- ing from about the neck and chest, especially the braces. Then standing at the patient's head, grasp the arms just above the elbows, and draw the arms gently and steadily upwards above the head, and keep them stretched upwards for two seconds (by this means air is drawn into the lungs). Then turn down the patient's arms and press them gently and firmly for two seconds against the sides of the chest (by this means air is pressed out of the lungs). Repeat those measures alternately, deliberately, and perseveringly about fifteen times in a minute, until a spontaneous effort to respire is perceived ; immediately upon which cease to imitate the movements of breathing, and proceed to induce circulation and warmth. 6. To promote warmth and circulation rub the limbs upwards with firm grasping pressure and energy using hand- kerchiefs, flannels, &c. Apply hot flannels, bottles of hot water, heated bricks, &c., to the pit of the stomach, the arm pits, between the thighs, and to the soles of the feet. 7. On the restoration of life a teaspoonful of warm water should be given ; and then, if the power of swallowing has returned, small quantities of wine, warm brandy and water, or coffee should be administered. 8. These remedies should be promptly applied, and, as death does not certainly appear for a long time, they ought only to be discontinued when it is clearly confirmed Absence of the pulsation of the heart is not a sure sign of death, neither is the want of respiration. Illuminating Gas. Illuminating gas is not found in mines ; but, as it is an important product of the distillation of coal and is largely used about collieries, it will be as well to say a word about it here. Its specific gravity depends upon the proportion of the heavier hydrocarbons present; in other words, specific gravity is a test of illuminating power. AIR. 119 1 2 candles gas is 14 1 6 J 8 j> 20 > 22 about 0-405 specific gravity. '43 '455 0-482 0-508 0-537 Its composition is variable, that of an average specimen is given on p. 113. The volume produced from a ton of coal depends upon the composition of the coal, as see Table XXX. TABLE XXX. AVERAGE PRODUCE OF A TON OF COAL. Newcastle Coal. Wigan Coal. Wigan Cannel. Gas cubic feet 9 CQO Q Q8o IO QOO Candle power 1 3 H 'A 21 '2C Coke Ibs I , C4.O I ,ci7 Zl ^ I d.^6 Tar, gallons 9 II 17 Ammoniacal liquor, gallons ... 10 20 18 j ("Gas Manager's Pocket Book.") Air. 1,000 cubic feet of air at temp. 32 Fahr. and 30 in. bar. weigh 80-9 Ibs. Air is a mixture of oxygen and nitrogen, with traces of some other gases, and vapour of water. Its composition varies a little in different places. 100 cubic feet of pure dry air contain : Oxygen 20-99 cu b- ft- Nitrogen 78-98 Carbonic Acid Gas . . 0*03 i oo 'oo cub. ft. (Angus Smith.) 120 ANALYSES OF AIR. 100 cubic feet of ordinary air contain : Oxygen . . . . 20*61 cub. ft. Nitrogen . . . . . 77-95 Carbonic Acid . . .0*04 Vapour of Water . . . 1*40 ,, i oo 'oo cub. ft. Ammonia . . . . \ Nitric Acid . . . . > Traces. Carburetted Hydrogen . j Traces in large town, Besides these gases, minute particles of solid matter are always present. Sundry Analyses by Angus Smith ; LONDON. Most Oxygen, Belsize Park . 2i'oio per cent. Least Oxygen, Lambeth . . 20795 Badly Ventilated Law Court . 20*49 Least CO 2 (open spaces) . . 0*0334 Most CO 2 (gallery of theatre) . 0*32 METROPOLITAN RAILWAY. Oxy gen... 2 0*7... Carbonic Acid . 0*1452 MINES. Average of Worst of Average of 8 Worst of 8 339 Mines. 339 Mines. Coal Mines. Coal Mines. O ... 20*26 ... 18-27 ... 20*74 ... 20-44 CO 2 ... 0*786 ... 2*73 ... 0-24 ... 0*42 Analyses of air in the returns of 9 Mines in Saxony, by Dr. Winkler : N. 75'6i74 to 78-565 % by vol. O. I775 1 to 19*689 CO 2 . 0*1 168 to 2-716 H 2 O. 2*5254 to 4-1904 ,, CH 4 . 0*01754 to 0-25576 ,, (N.E.I., xxxii., abs. p. 25.) VOLUME REQUIRED, 121 Purification by: Diffusion, the wind, rain, plants, and animals. Vitiation by : Withdrawal of oxygen, as in the breathing of men and horses ; the combustion of lamps, candles, and gunpowder ; the conversion of iron pyrites into sulphate of iron, 2FeS 2 + 4O 2 = 2FeSO 4 + S 2 ; the oxidation of small coal; &c., &c. And Vitiation by the introduction of foreign substances, such as the occluded gases, the products of combustion and respiration, vapour of water, and coal dust. Angus Smith considers that two miners, using \ 1>. candle and 12 oz. of powder, will produce 25 J cub. ft. of CO 2 in 8 hours. Thomas, quoting Boussingault, says that a horse will produce 155 cub. ft. of CO 2 in 24 hours. But the quantity, both in men and horses, is very variable, and, as certain organic exhalations are also given off in breathing which, though they may not be capable of detection by chemical analysis, are more deleterious than CO 2 , no esti- mate of the volume of air required can be formed from an attempt to calculate the CO 2 produced. The quantity of air required depends upon the conditions of each mine. In the North of England, the volume seems to vary from 100 to 500 cubic feet per min. per person em- ployed, and from 30 to 160 cubic feet per min. per ton of coal worked per day. The velocity in the workings should be about 4 feet per second. Authorities; " Air and Rain," Angus Smith; The Chester- field and Derbyshire Inst. Trans., x. ; " Coal and its Uses," Green, Miall, etc. ; Papers by Davy, communicated to the Royal Soc. (See Royal Soc. Trans., 1816.) The Report of the Select Com., 1835 '> Tne Journal of the British Soc. of Mining Students, vi. ; J. J. Atkinson on " Ventilation ; " also, Papers by the same author in the Transactions of the North of England Institute ; " Ventilation of Coal Mines," Fairley; "Coal, Mine Gases, and Ventilation," Thomas; J. Wales' Papers, Trans. N.E.I., vi. and vii.; "Hist, of Coal Mining," Galloway; Proceedings Royal Soc., xxiv. toxxxvii.; Report of the Accidents in Mines Commission, 1886; "Ex- plosions in Coal Mines," Atkinson; "Ambulance Lectures," Weatherly; and "Shepherd's First Aid to the Injured," Bruce. VENTILATION. A WIND, either upon the surface or in the mine, results from a difference of pressure ; the air passing from the place where the pressure is high to the place where the pressure is low. If H = Height in feet of a column of air of the density of the flowing air that will, by its weight, produce the difference of pressure. V = Velocity of the wind in feet per second (151.) H = ^ .-. V = 8^H: This formula applies to all fluids, H being taken in feet of the fluid in question. In practice the actual velocity of an air current is much retarded by friction ; and it is, therefore, necessary to study the laws that govern the resistance that air meets with in mines. The Three Laws of Friction.* (1) The pressure required to overcome the friction of the air increases and decreases in exactly the same propor- tion that the area or extent of the rubbing surface, exposed to the air, increases or decreases. If P = the ventilating pressure, L = the length of a drift, O = the perimeter, do. Then LO = the rubbing surface, And P varies as LO. (2) The pressure per unit of area required to overcome * P also varies as the density of the air ; but the variations in density are so small that this may be neglected. FRICTION OF AIR. 123 the friction of the air increases and decreases inversely as the sectional area of the drift increases and decreases. If P = the ventilating pressure per unit of sectional area of the drift, A = the sectional area of the drift, Then P varies as A (3) The pressure required to overcome the friction of the air increases and decreases in the same proportion that the velocity squared of the air increases and decreases. If P = the ventilating pressure, V = the velocity of the air, Then P varies as V 2 . It follows from this that if P = the ventilating pressure pei unit of sectional area, KLOV 2 P may be obtained by means of a very delicate baro- meter, or by means of a water-gauge ; L, O, A, and V, by measurement, treating each section of the mine separately. K is a constant to be found by experiment : it depends upon the units used. It is called the coefficient of friction; and is equal to the ventilating pressure required to over- come the resistance that a unit of air flying with unit velo- city would meet with in circulating round a mine of unit area, and having unit rubbing surface. When P is taken in Ibs. per square foot. L do. feet. O do. feet. V do. feet per minute. A do. in square feet. According to the experiments of MM. Devillez, Raux, &c., K = 0*000,000,009,36 (approximately) for the whole of a mine ; but, in the case of clear smooth shafts alone, K = 0*000,000,003,6. That is to say a ventilating pressure of 0*000,000, 009,36 Ibs. 124 EQUIVALENT ORIFICE. per sq. ft. would be required to force i c. f. per min. through a mine i sq. ft. in area, and having a rubbing surface of i sq ft. It is more convenient to take V in thousands of feet per min. ; in which case K = 0*009, 36 anc ^ 0*003,6 respectively. A great many important facts may be deduced from formula (152), as see Fairley's "Ventilation of Coal Mines." Ihe Equivalent Orifice. Air in passing through an open- ing in a thin plate meets with resistance ; and M. Murgue has pointed out the convenience of assimilating the work- ings of a mine to such an opening in calculations for venti- lating purposes. This opening he has named the equivalent orifice. To find the equivalent orifice for any given mine : Let Q = Quantity of air in cubic feet per second passing through the opening (i.e., circulating round the mine). h a = Ventilating pressure in feet of air column, required to overcome the resistance of the mine. A = opening in thin plate in square feet (i.e., equivalent orifice). k = coefficient of contraction of orifice (/.., 04 V 2 = * We may say, therefore, that : In a perfect fan the theoretical depression is double the height due to the tan- gential velocity. If H = as above. P = Ventilating pressure in Ibs. per sq. ft. WG = Water gauge in inches. d = density of water = 1000. d' = density of air =1-2 approx. at ordinary pressure and temperature. Then (163.) P = 5 - t Q X 12 I'2 X 12 I,OOO The following formulae are taken from Mr. A. L. Steaven- son's translation of M. Murgue's work, to which students are referred for details : Let H = the theoretical depression in feet of air column that a perfect fan would give if its eye were shut off from the mine and atmosphere. h a = effective depression in feet of air column; i.e., the ventilating pressure required to overcome the resistance of the workings = the water gauge in the fan drift. h = useless depression in feet of air column; i.e., the ventilating pressure required to overcome the resistance the air meets with in passing through the fan. To obtain this the communication between the fan-eye and the workings must be closed, and the eye connected direct with the atmosphere. 130 FAN FORMULA. Q = Quantity of air in cubic feet per second. A = Equivalent orifice in sq. ft. (see p. 124). O = Orifice of passage in sq. ft. ; i.e., the area of a hole in a thin plate which would offer the same resistance to the air that the fan offers. k = coefficient of efficiency of fan (varying in the case of well designed fans from 0*5 to o - 8). g = gravity, say 32-19. u = Tangential speed of fan in feet per second. Then- (165.) H = h a + h (166.) H = | ( See 'S3-) A = ^ 7 % r (167.) = (170.) (171.) COMPRESSIVE VENTILATION. 131 And for practical calculations : ku2 (176.) Q A/ A2 Yi + ni o 2 I believe Nasmyth was the first to apply the fari to venti- lating purposes. His machine was an open running fan with straight blades, and gave a very small efficiency. To Guibal belongs the greater part of the credit for our present, comparatively speaking, perfect machine. If Q = total volume of air circulating in a mine, q = a portion of Q due to any cause, say a fan. v = the rest of Q due to some other cause, say a furnace. (177-) Q= \/q 2 +v 2 (v.) Varying Capacity Machines* See description of Lemielle's, Nixon's, Struve's, Cooke's, and Roots' blowers in Trans. N.E.I., i., vi., xi., xvi., xviii., xix., xxx. (B.) Compressive Ventilation. This has been tried in Germany (see Trans. N.E.I, xxxiv. abs. p. 49), though not in England, so far as I am aware. Many persons consider that such a method of ventilation would be preferable to the exhaustive system. (See Colliery Guardian^ 1880, 2d part.) The waterfall is convenient as a temporary expedient; and either the water-fall or wind- cowl may be used for the permanent ventilation of a small non-fiery mine. * These machines are best suited to mines with small equivalent orifices (less than 20 sq. ft. ). There are not many of them in use in England. K 2 132 RELATION BETWEEN VOLUME, PRESSURE, <&*. Relation between Volume, Pressure, &c. The ventilating pressure varies as : The depth of the upcast shaft (furnace ventilation). The difference of temperature between upcast and down- cast. The HP of the ventilating machine or furnace. The quantity of coals burned. The quantity of air circulating varies as : The revolutions of the fan. The tangential velocity of the fan. The y of the ventilating pressure. The The The The of the depth of the upcast (furnace ventilation). of the difference of temperature (nearly, as see P- 126). _ of the HP of the ventilating machine. of the coals burned. Authorities : Trans. N.E.L, i. and vi., on the Steam Jet; xviii. and xix., on the Furnace; xxvi. and xxxi., on the Fan ; Books and Papers by Fairley and Atkinson already mentioned ; Murgue's " Theory and Practice of Centrifugal Ventilating Machines," by A. L. Steavenson. TABLE XXXII. TABLE OF HYPERBOLIC LOGARITHMS (FORMULAE 61, 85, ETC.). Nos. Logarithm Nos. Logarithm Nos. Logarithm Nos. Logarithm I '01 009 I'll 104 21 190 31 270 I'O2 OI9 1*12 113 22 I 9 8 32 277 1-03 029 I-I3 122 2 3 207 '33 285 1-04 039 I-I4 131 24 215 '34 292 1-05 048 1*15 139 25 22 3 '35 3 00 I -06 058 1-16 148 26 231 36 307 1-07 I -08 06 7 076 1-17 1-18 35 27 28 239 246 '37 38 3H 322 1-09 086 1-19 173 2 9 254 '39 329 1*10 095 I '20 182 3 262 40 336 HYPERBOLIC LOGARITHMS. 133 TABLE XXXII. continued. Nos. Logarithm Nos. Logarithm Nos. Logarithm Nos. Logarithm 41 '343 81 '593 2'2I 792 2'6l '959 42 350 82 598 2 '22 797 2-62 963 '43 '357 '83 '604 2-23 802 2-63 966 '44 364 84 609 2-24 806 2-64 970 45 371 85 615 2-25 810 2-65 '974 46 378 86 620 2-26 815 2-66 978 '47 385 87 625 2-27 819 2-67- 982 48 392 88 6 3 I 2-28 824 2-68 985 '49 398 89 636 2 '29 828 2-69 989 'SO '405 90 '641 2-30 832 270 '993 'SI 412 91 647 2-31 837 271 996 52 418 92 6 5 2 2-32 841 272 I'OOO '53 425 '93 657 2'33 845 273 I '004 '54 43i 94 662 2'34 "850 274 1-007 55 438 '95 66 7 2'35 854 275 I 'Oil 5 6 '444- 96 672 2-36 858 276 1-015 '57 45i '97 678 2-37 862 277 1-018 5 8 '457 98 68 3 2-38 867 278 I'O22 59 463 '99 688 2-39 871 279 1-026 60 470 2'00 693 2-40 875 2-80 I '029 61 476 2'01 698 2-41 879 2'8l I'033 62 482 2'O2 703 2-42 883 2-82 1-036 63 488 2-03 708 2-43 887 2-83 I-O4O 64 '494 2-04 712 2-44 891 2-84 1-043 65 500 2-05 717 2'45 896 2-85 1-047 66 506 2'06 722 2-46 900 2-86 I'O5O 67 512 2-07 727 2-47 904 2-87 i '054 68 518 2-08 732 2-48 908 2-88 i '057 69 524 2-09 737 2-49 912 2-89 1-061 70 530 2'10 741 2-50 916 2-90 1-064 7i 536 2'II 746 2-51 920 2-91 i -068 72 542 2'12 75i 2-52 924 2-92 1-071 73 548 2-13 756 2'53 928 2-93 1-075 74 '553 2-14 760 2'54 932 2-94 1-078 75 '559 2-15 765 2'55 936 2'95 1-081 76 565 2-16 770 2*56 940 2-96 1-085 77 570 2-17 774 2 '57 '943 2-97 i -088 78 576 2'l8 779 2-58 '947 2-98 1-091 79 582 2-19 783 2'59 95i 2-99 1-095 i -80 587 2 '20 788 2-60 '955 3'oo 1-098 134 HYPERBOLIC LOGARITHMS. TABLE XXXII. continued. Nos. x>garithm Nos. Logarithm Nos. ^ogarithm Nos. Logarithm 3'01 101 3-4I I '226 3-8i 1-337 4'2I i '437 3-02 105 3-42 1-229 3-82 I-340 4-22 **439 S'03 108 3' 43 I '232 3-83 1-342 4-23 1-442 3'4 in 3 '44 i '235 3-84 1-345 4-24 1-444 3-oS "5 3'45 1-238 3-85 I-348 4-25 1-446 3'o6 118 3 '46 1-241 3-86 I-350 4-26 1-449 3-07 121 3'47 1-244 3-87 I"353 4-27 I-45I 3-08 '124 3H8 1-247 3-88 1-355 4-28 1-453 ! 3-09 128 3 '49 1-249 3-89 I-358 4-29 I-456 3-10 131 3 '5 i -252 3-90 1-360 4-30 I-458 3-11 134 3-5i 1-255 3 '91 I-363 4-3I 1-460 3-12 137 3-52 1-258 3-92 I- 3 66 412 1-463 3-I3 141 3 '53 1-261 3 '93 1-368 433 1-465 3*14 144 3'54 1-264 3'94 I-37I 4'34 1-467 3-I5 147 3'55 1-266 3-95 1-373 4-35 1-470 3'i6 'ISO 3-56 1-269 3-96 I-376 4-36 1-472 3-17 153 3'57 1-272 3-97 1-378 4'37 1-474 3'i8 I 5 6 3-58 1-275 3-98 1-381 4-38 1-477 3-I9 160 3 '59 1-278 3'99 1-383 4-39 1-479 3-20 163 3-6o 1-280 4 - oo 1-386 4-40 1-481 3-21 166 3'6i 1-283 4 -oi 1-388 4HI 1-483 3-22 169 3-62 1-286 4-02 1-391 4*42 1-486 3 '23 172 3-63 1-289 4-03 i 393 4'43 1-488 3 '24 175 3 "64 1-291 4-04 1-396 4 '44 1-490 3-2S 178 3^5 1-294 4-05 1-398 4-45 1-492 3'26 181 3-66 1-297 4*06 1*401 4-46 1-495 3 '27 184 3-67 1-300 4-07 1-403 4'47 1-497 3-28 187 3-68 1-302 4-08 1-406 4-48 1-499 3*29 190 3-69 1-305 4-09 1-408 4'49 1-501 3 '30 193 370 1-308 4-10 1-410 4-50 1-504 3-3i 196 371 1-311 4-11 I-4I3 4-5I 1-506 3-32 199 372 i'3i3 4-12 1-415 4-52 1-508 3 '33 202 373 1-316 4'i3 1-418 4-53 1-510 3'34 205 374 1-319 4-14 1*420 4'54 1-512 3'35 208 375 1-321 4-15 1-423 4'55 I-5I5 3-36 211 376 1-324 4'i6 1-425 4 '56 I-5I7 3 "37 214 377 1-327 4-17 1-427 4-57 I-5I9 3-38 217 378 1-329 4-18 1-430 4-58 1-521 3 '39 '22O 379 1-332 4-19 1-432 4-59 I-523 3-40 223 3'8o i-335 4 -20 1-435 4-60 1-526 HYPERBOLIC LOGARITHMS. 135 TABLE XXXII. continued. Nos. jOgarithm Nos. jOgarithm Nos. ^ogarithm Nos. Logarithm 4-61 1-528 5-01 1*611 5-4I 1*688 5'8l 1759 4 '62 I '530 5-02 1-613 5-42 1*690 5-82 1761 4*63 I'532 5-03 1-615 5 '43 1*691 5-83 1763 4-64 i '534 5 '04 1-617 5"44 1*693 5-84 1*764 4'65 I-536 5-05 1-619 5-45 I-695 5-85 1766 4-66 i '539 5-o6 1*621 5-46 1-697 5-86 1768 4-67 i '54i 5-07 1-623 5'47 1*699 5-87- 1769 4-68 i '543 5-08 1-625 5-48 1*701 5*88 1771 4-69 1*545 5-09 1-627 5'49 1*702 5-89 1773 470 1-547 5-io 1*629 5-5o 1704 5-90 1*774 471 1-549 5'n 1*631 5-5i 1706 5-9i 1776 472 i'55i 5-12 1-633 5-52 1*708 5-92 1778 473 i'553 5-13 1-635 5-53 1710 5-93 1*780 474 1-556 5-14 1-637 5'54 1-711 5'94 1*781 475 I-558 5-I5 1-638 5-55 1713 5-95 1-783 476 1-560 516 1*640 5-56 1715 5-96 1785 477 1-562 5-17 1-642 5-57 1717 5-97 1786 478 1-564 5-18 1*644 5-58 1719 5-98 1788 479 1-566 5-19 1*646 5'59 1*720 S'99 1-790 4-80 1-568 5-20 1-648 5-60 1722 6*00 1791 4-81 1-570 5'2i 1-650 5-6i 1724 6*01 1793 4-82 1-572 5-22 1*652 5*62 1726 6*02 1795 4-83 1-574 5-23 I-654 5-63 1728 6*03 1796 4-84 1-576 5'24 1-656 5-64 1729 6*04 1798 4-85 1-578 5-25 1-658 5-65 1731 6-05 i -800 4-86 1-581 5-26 i *66o 5-66 1-733 6-06 1-801 4-87 1-583 5-27 1-662 5-67 1735 6*07 1-803 4-88 1-585 5-28 1-663 5-68 1736 6*08 1*805 4-89 1-587 5-29 1-665 5-69 1738 6*09 i -806 4-90 1-589 5-30 1-667 57o 1*740 6*10 i -808 4-91 i-59i 5-3i 1*669 57i 1742 6*ii 1-809 4-92 1-593 5-32 1*671 572 1743 6*12 1*811 4-93 1-595 5-33 1-673 573 1745 6*13 1*813 4 '94 1-597 5'34 1-675 574 1747 6*14 1*814 4'95 1-599 5-35 1*677 575 1749 6*15 1*816 4-96 1-601 5-36 1*678 576 1750 6*16 1*818 4'97 1-603 5"37 1-680 5-77 1752 6-17 1*819 4-98 1-605 5-38 1*682 578 1754 6-18 1*821 4 '99 1-607 5'39 1*684 579 1756 6*19 1*822 5'oo 1-609 5-40 1*686 5*80 1757 6*20 1-824 136 HYPERBOLIC LOGARITHMS. TABLE XXXII. continued. Nos. Logarithm Nos. Logarithm Nos. i Logarithm Nos. Logarithm 6-21 I-826 6-61 I-8S8 7-01 1-947 7-4I 2'OO2 6'22 I-827 6-62 1-890 7-02 1-948 7-42 2-004 6-2 3 1-829 6-63 1-891 7-03 1-950 7-43 2-005 6-24 1-830 6-64 1-893 7-04 1-951 7'44 2 'OO6 6-2 5 I-832 6-65 1-894 7-05 1-953 7-45 2-Oo8 6-26 1-834 6-66 1-896 7*06 1-954 7-46 2 '009 6-27 1-835 6-67 1-897 7-07 1-955 7-47 2'QIO 6-28 1-837 6-68 1-899 7-08 1-957 7-48 2-012 6 '29 1-838 6-69 1-900 7-09 1-958 7H9 2-OI3 6-30 1-840 6-70 1-902 7-10 I -960 7-50 2-014 6-31 1-842 671 1-903 7-11 1-961 7-5I 2-016 6-32 1-843 672 1-905 7*12 1*962 7-52 2-017 6-33 1-845 673 1-906 7-i3 1*964 7-53 2-018 6'34 1-846 674 1-908 7*14 1-965 7-54 2'O2O 6-35 1-848 6-75 1-909 7-15 1-967 7-55 2-021 6-36 1-850 676 1*911 7-16 1-968 7-56 2-022 6-37 I-85I 677 1*912 7-17 1-969 7-57 2-024 6-38 1-853 678 1-913 7-18 1-971 7-58 2*025 6'39 1-854 6-79 I-9I5 7-19 1-972 7-59 2-026 6 '40 1-856 6-80 1-916 7-20 1-974 7'60 2-028 6-41 I-857 6-81 1-918 7-21 1-975 7-61 2*029 6-42 1-859 6-82 1-919 7-22 1-976 7-62 2-030 6'43 1-860 6-83 1-921 7-23 1-978 7-63 2-032 6-44 1-862 6-84 1-922 7-24 1-979 7-64 2-033 6'4S 1-864 6-85 1*924 7-25 1*981 7-65 2*034 6-46 1-865 6-86 1-925 7-26 1-982 7-66 2-036 6-47 1-867 6-87 1-927 7-27 1-983 7-67 2-037 6-48 1-868 6-88 1-928 7-28 1*985 7-68 2-038 6-49 1-870 6-89 1-930 7-29 i 1-986 7-69 2-039 6-50 1-871 6-90 1-931 7*30 | 1*987 7-70 2-04I 6-51 1-873 6-91 1-932 7-31 i 1*989 7-71 2*042 6-52 1-874 6-92 i'934 7-32 1-990 7-72 2-043 6-53 1-876 6-93 i'935 7-33 ! i-99i 773 2-045 6 '54 1-877 6-94 i"937 7'34 1-993 7-74 2-046 6-55 1-879 6'95 1-938 7'35 ' 1-994 7'75 2-047 6-56 1-880 6-96 1-940 7-36 1-996 776 2*048 6'57 1-882 6-97 1-941 7-37 1-997 777 2-O5O 6-58 1-884 6-98 1-943 7-38 1-998 778 2-05I 6'59 1-885 6-99 1-944 7-39 2-000 779 2-052 6-60 1-887 7-00 1-945 7 -40 2 -ooi 7*80 2-054 HYPERBOLIC LOGARITHMS. 137 TABLE XXXII. continued. Nos. Logarithm Nos. Logarithm Nos. Logarithm Nos. Logarithm 7'8l 2-055 7'86 2 - o6i 7-9I 2-068 7-96 2-074 7-82 2-056 7-87 2-063 7-92 2-069 7'97 2-075 7-83 2-057 7-88 2-064 7 '93 2-070 7-98 2-076 7-84 2-059 7-89 2-065 7 '94 2-07I 7 '99 2-078 7-85 2 -060 7-90 2-066 7'95 2-073 8-00 2-079 Specific Gravity. As a cubic foot of water weighs 1,0.00 ozs., the weight of any substance can be got by multiplying its specific gravity by 1,000. TABLE XXXIII. SPECIFIC GRAVITIES. Metals. Platinum (laminated) Pure Gold (hammered) Gold 22 carat (do.) . Mercury Lead (cast) Pure Silver (hammered) Copper (cast) . Marble (white Italian) Slate (Westmoreland) . Granite (Aberdeen) . Paving Stone Mill Stone Grindstone . . Elm . Fir (Riga) . Larch Mahogany (Spanish) The specific gravity of the gases is given in Table XVI., p. 104. 22-0690 Brass (cast) 8-3958 19-3617 Steel (hard) . 7-8163 17*5894 Iron (cast) . 7 -2070 13-5681 ,, (wrought) 7-7880 11-3523 Tin (cast) . 7-2914 10-5107 Zinc (cast) 7-1908 8-7880 Stones and Earth. 2-638 Portland Stone 2-145 2791 Coal (Newcastle) . 1-270 2-625 Brick (Red) . 2-168 2-4158 Clay . i -919 2-4835 Sand (River) . i -886 2-1429 Chalk (mean) 2-315 Woods (Dry\ &c. . 0-588 Oak (English) . . 0-934 0753 Teak (Indian) . 0-657 . 0-522 Cork . 0-240 . 0-800 Sea water . . i -027 (Twisden's " Mechanics.") EXAMPLES OP THE USE OF THE FORMULA. (i.) What is the breaking load of a lo-inch hemp rope? By formula (i) we find that : W = o*25 x 10 x 10 = 25. Answer, 25 tons. (2.) What size of round iron-wire winding rope would be required for a pit 100 fathoms deep, and with a full cage weighing 3 tons, taking 8 as factor of safety ? By formula (u) we have : c = 8 I '2 X 224O Anzwer, a 4^ inch rope. (3.) What must be the dimensions of a round, taper, plough steel, wire rope for a pit 500 fathoms deep, and a working load of 7 tons, at the top, bottom, and 100 fathoms from the bottom ? By page 1 8 we find that : The safe working load is 13,440 Ibs. per sq. inch of section. The area, therefore, of the rope at the bottom must be 7 X 2>24 = i -166 sq. inches. I3.440 The area at the top by formula (14) and Table VII. is : A= 1-166 x 1-4549= 1-696. The area at 100 fathoms from the bottom by the same formula and Table is : A=ri66 x 1-0778= 1-256. EXAMPLES OF THE USE OF THE FORMULAE. 139 Answers, Area at top .... 1*166 sq. in. bottom . . . 1*696 100 fms. from bottom . 1*256 In this way the area of a taper rope at any point of its length may be obtained. (4.) What should be the thickness of the plates of a single riveted iron boiler, 5 ft. diameter, to stand a working pressure of 40 Ibs. above the atmosphere, taking 8 as factor of safety? By formula (25) we have : TH = 4 X5XI2 x 8 = 0-384 inches. 50,000 Answer, f inches. (5.) What should be the thickness of an oak spherical dam with external radius 1 5 feet to withstand a pressure of 50 fathoms of water. By formula (43) we have : r= 15 feet = 1 80 inches. T= 10,000. p = 50 fathoms = 130 Ibs. per sq. in. Then _____^__ K=i8o{i- l/i- '5x130 I V 10,000 J - ,3/i-o-i 9 5 j=i8o{ i- = i8o| i 0-93024 I =12-55. Answer, 12-55 inches. (6.) If the resistance offered by a set of railway carriages be 10 Ibs. per ton, how many tons weight could a horse drag? 140 EXAMPLES OF THE By Table XIV. we see that a horse can overcome a resist- I2O ance of 120 Ibs. He could therefore draw = I2 10 Answer, 12 tons. (7.) What force must be exerted to draw a tub weighing 1 6 cwt. up an incline rising 2 inches to the yard, the tub, wheels and axles being 12^ and i\ inches in diameter respectively ? By formula (131) : WTT Resistance = m W + ILtr . JLi and by formula (127) : m = 0*0882 x 5_ = o*oio6. 12.5 and we have given : W= 1 6 cwt. = 1,792 Ibs. H = 2 inches. L = i yard = 36 inches. .-. R = 0-0106 x 1,792 + !iIJL = 1 18-55. 3 6 Answer, n8J Ibs. We see by Table XIV., p. 38, that a horse will exert a force of 120 Ibs. Therefore one horse would be required to draw the tub. (8.) At what inclination must a self-acting incline 600 ft. in length be laid in order that it may run a set of 10 tubs in one minute the weight of a full tub being 15 cwt, of an empty tub 6 cwt., of the rollers and sheave 700 Ibs., and of the rope 200 Ibs. ? First find the resistance of friction as explained in formula (129), and let it be 16-8 Ibs. for a full tub, and 6-72 Ibs. for an empty tub, in other words, o'oi of the weight. The friction of the rollers and sheave may be estimated at about 0-03 of their weight. USE OF THE FORMULAE. 141 Then L = 6oo, H = ? F = (io x 15 x 1 12) = 16,800 Ibs. E = (io x 6 x 1 1 2) = 6, 7 20 Ibs. T = 60 seconds. =32 R= 200 Ibs. 8 = 700 Ibs. 7 = 0'OI,#z' = 0'O3. W= (16,800 + 6,720+ 200 + 700) = 24,420 lbs. t and by formula (138) : 24,420 x 2 x 600 H ^ -oi (16,800 + 6,720) + -03 x 700 + -- L 16,800 - (6,720 + 200) 235 + 21 + 254 _ 510 16,800-6,920 9,880 L 9,880 9,880 That is to say, the height of the incline must be 30-96 ft. which, in a length of 600 ft, is equal to nearly i in 20, or i '8 in. to the yard. In laying out the incline, the average gradient should be i '8 in. per yard ; but it should be rather steeper at the top, and rather flatter at the bottom. (9.) What will be the position of meetings in a pit 237^- fathoms deep when the rope is "ji inches thick, the diameter of the drum at the lift 16 ft. 2 in., and the revolutions of the drum 25! per winding? By formula (115) : n = -1=12-8125. r=97'355-'- 2r = I 94'7i- Then : x 12- -8125 < 194*71 + (ir8i25 x -71) i = 40-2517 x 203*097 = 8,174 inches, and 8,174 inches is 113*51 fathoms. Answer, 113^ fathoms from the bottom of the shaft. 142 EXAMPLES OF THE (10.) Design a non-condensing pumping engine to force 1,000 gallons per minute, 50 fathoms vertically, with a pressure of 30 Ibs. of steam above the atmosphere. The pressure in the boiler will be 30+ 147 = 45 Ibs. (say), and the steam, therefore, may be cut off at f of the stroke, reducing the pressure of the exhaust to f x 45 = 18 Ibs., or 3 Ibs. above the atmosphere. The mean pressure by formula (61) will be : i + Hyp. log. = 18 (i + Hyp. log. 2-5). By Table XXXII., p. 132, Hyp. log. 2-5 is 0-916 and i8x 1-916 = 34*488 Ibs. Deduct from this the back pressure, i.e., the pressure of the atmosphere, and we get : Mean effective pressure on piston = 20 Ibs. (say). The work to be done, expressed in units of horse-power, is by formula (49) : 10 x 1,000 x co x 6 = 90-9. i x 33,000 Add 50 / for friction and we get (say) 136 as the horse- power of the engine required. We will assume 6 feet as the length of stroke. (If on trial it is not suitable, we must assume some other length, and make our calculations over again.) Then by formula. (122) the speed of piston should be : \/6 x 60 = 2-45 x 60 = 147 ft. per minute, and the area of the piston by formula (60) is : 33,000 x 136 . =1,526 sq. inches; 20 x 147 and the diameter by formula (65) is : I >5 26 ^ 44 - I inches (say) 45 inches. 7854 The ram for pumping the water should be double acting, and will have the same stroke as the engine, viz. : 6 ft. USE OF THE FORMULA. 143 Allowing 5/ loss of water due to leakage, etc., its diameter by formula (121) will be : V / - 2 10 = (say) a 14$ ram. 0-034 x 6 x 24-5 The answer then is : An engine with one 45" cylinder, by 6' stroke ; and a double-acting ram i^\" diameter, by. 6' stroke. (i i.) How many egg-ended boilers 36' long by 5' diameter will be required to drive the above engine ? Each boiler will have a fire-grate area of 25 sq. ft. And the effective heating surface in sq. yards (see p. 49) will be : 3'i4i6 x 5 x 36 3 - x = 23-56 sq. yards. The number of cubic ft. of water evaporated into steam per hour will be by formula (75) : 6 x 25 = 24-27 cubic ft. per hour ; and this is equal, by Table XVI., to 24*27 x 562 = 13,640 cubic ft. of steam at 45 Ibs. The engine consumes : 2 1526 5 x 12 x 12 x 24 ' 5 x 6o = 37>3 8 7 cu bic ft. of steam per hour, and will, therefore, require : ^ = 274 boilers, say 3 boilers. (12.) How many tons of small coal would the above boilers consume per fortnight ? As the engine does not require the full power of the boilers, we may take the consumption of coal at 18 Ibs. per sq. foot of grate per hour, instead of at 20 (see p. 49) ; and the consumption will be : 18 x 25 x 3 x 24 x 14 - 2?240 =200 tons (say). (13.) What should be the dimensions of a chimney to supply draught for two Lancashire boilers, each having 80 ft. of flue length, and each consuming 300 Ibs. of coal per hour? 144 EXAMPLES OF THE By p. 126, 300 Ibs. of coal requires 90,000 cubic ft. of air to burn it, and this air will be doubled in volume when dis- charged from the chimney. For the two boilers, therefore, 360,000 cubic ft. of air per hour must be discharged, which is equal to 100 cubic ft. per second. We may take 20 ft. per second (in practice the velocity of discharge varies very much) as a convenient velocity of discharge, from which it follows that the area of chimney at the top should be 5 sq. ft., say 2. 7" in diameter. Then by formula (78) we have : L = height of chimney, including length of flue (where there is more than one boiler we do not take the aggregate length of the flues, but the length of one only). For the height of the chimney we must assume a quantity, say 50 ft., so that L= 130, and v = 2o, and D = 2'.7", say 2 '6 ft. Then 20 X 20 (< 13 + 1 Q C "jd.8 ft. 2 X 32'2 2-6 ; 9 ^ To produce this motive column we require by formula (79) a chimney : H- 95-48 95'48 : TOO ft 519 We see then that our assumption of 50 ft. for the height of the chimney was too little, and that with a velocity of 20 ft. per second we should require a chimney tall and narrow We will, therefore, try a height of 64 ft., and a velocity of 1 6 ft. per second. The area at the top, for a discharge of 1 6 ft per second, is -^- = 6*25 sq. ft, which corresponds to a diameter of 2-82 ft. And : 16 x 16 ) = 6rSoft, and by formula (79): 6r8 519 USE OF THE FORMULA. 145 64 ft. then is rather too high, and we may say that a chimney 62 ft. high, and 2'.io" diameter at the top, would satisfy our requirements. The inside diameter at the bottom may be the same as the inside diameter at the top ; but should not be less, and is usually made rather more. (14.) How many units of work are required to compress i Ib. of air at 68, and under a pressure of one atmosphere to J of its volume : ist, isothermally ; 2nd, adiabatically ? (i.) Isothermally, by formula (85). P 1 =i47 x 144 = 2,116*8 Ibs. per sq. ft Vj= 13-3 cubic feet. ^ = 6 ; the hyp. log. of which by Table XXXII., is i -79. 2 Then : U = 2,u6'8 x 13-3 x 179 = 50,394. (2.) Adiabatically, by formulae (87 & 84). T! = 68 + 459 = 5 2 7 absolute temp. W = one Ib. i.e. = i. //5\ '408 T 2 = (by formula 84) 527 ( - Log. 6 = 07781513 408 62252104 311260520 3174857304 corresponds to 2-077. ' T 2 = 527x2-077 = 1,094. Then, by formula (87): U = 130-3 (1,094 - 527) = 73,680. Answers : ist. Isothermally, 50,394 units of work. 2nd. Adiabatically, 73,680 do. 146 EXAMPLES OF THE (15.) A, B, and C are three bore holes; the depths of which, from the same horizontal plane to a seam of coal, are respectively 100, 106, and 108 yards. From A to B is 100 yards, and from A to C 120 yards. The angle in a horizontal plane between A B and A C is 30. What is the direction of the dip of the seam, and the angle of dip ? By formulae (105 & 106). a=ioo; a' =120; W = $o; d = 8; d' = 8. Then: 6 x 120^ 0>t . Tan V- _* = 2-04 = 63 53'. /6XI20 \ 100 s x o'ooo J Tan S= ^- = 0-089-5 7'. 100 x 0*8979 The dip is at right angles to the strike, and the strike of the bed makes, we see, an angle of 63 53' with the line A B. And the angle of dip is 5 7'. Suppose B to be due north of A, and C to lie on the east side of B : the seam will dip 5 7' ; N. 26 7' E. (16.) What is the cost of boring a hole on the diamond system, 250 fathoms deep? 250 fathoms is 1,500 feet, and by p. 72, the price for the first step is ^30, the number of steps is 15, and the increase in price for each step is ^30. Then by formula (107) : c= | 2x30 + (15 1) 30 j -- = 3,600. Answer ^"3,600. (17.) What is the ventilating pressure in Ibs. per square foot required to circulate 10,000 cubic feet per minute through a drift two miles long : i st. When the drift is circular, 7-98 feet in diameter. 2nd. When the drift is square, 7*071 feet high. 3rd. When the drift is oblong, 5 feet x 10 feet? We first note that the area of each of these drifts is practically the same, viz., 50 square feet ; and that, theres USE OF THE FORMULAE. 147 fore, the velocity of the air will be the same in each, viz. : I0>00 = 200 feet per minute ; or 0*2 thousands of feet per 5 minute. But the perimeters vary. By formula (152). KLOV P _ A A '009 X 2 X 1760 X 3 X 0*2 X O'2 = 0-076 x O. Then ist. (circular drift) P = 0*076 x 25*07 = 1*90. 2nd. (square drift) P = o*o76 x 28*28 = 2*15. 3rd. (oblong drift) P = 0*076 x 30*00 2*28. Answer. 1*90, 2*15, and 2*28 Ibs. per square foot respec- tively. From which we see that the circular drift offers the least resistance. (18.) If the depth of the shafts of a mine ventilated by a furnace be 1,000 feet, the temperature of the downcast 41, of the upcast, 141, and the height of the barometer, 30 inches ; what will the ventilating pressure be in Ibs. per square foot ? By formula (159) : / = l V X I,OOO 459 + 41 459 *- J = (0*079518 0*066265) x 1,000. = i3 >2 53- Answer. 13! Ibs. per square foot. (19.) What should be the indicated horse-power of a hauling engine to work a plane 1,200 yards in length with two curves of 58 and 82 respectively : the maximum work being to draw the full set, weighing 35,840 Ibs., up a bank at the inbye end, rising i in 12, at the rate of 4 miles *n hour ? Assuming that the coefficient of friction of the tubs = *oi ; the weight of ropes, rollers, and sheaves = L 2 148 EXAMPLES OF THE 21,000 Ibs. ; the main rope drums at curves are 1 8" dia- meter with 3-i" axles Then the pull, or force, to be exerted by the engine is : 1. Friction of set 35,840 x *oi, as see for- mula (127),= ................................. 358-40 2. Gravity of set 35,840 -f- 12, as see for- mula (130), = ................................. 2,986-66 3. Friction of rope on rollers, &c., 2 1,000 x "03, as see m', p. 98, = ........................... 630-00 Total resistance on straight road ...... 3>975'6 To this must be added the resistance due to the friction of the main rope upon the drums at the curves, viz : First curve with angle of 58, the pressure upon the drums (or sheaves, as the case may be) by the parallelogram of forces (see Twisden's " Practical Mechanics," 4th edition, pp. 54 and 83), will be : Second curve with angle of 82 gives in the same way : The total pressure on the drums at the curves is therefore 12,963 Ibs. ; and the friction due to this pressure is, by irmula (114) 12,963 x -07x3-5 lg =176-44 Ibs. The total force the engine must exert is therefore : 1. Friction of set ..................... 358-40 Ibs. 2. Gravity of set ..................... 2,986*66 3. Friction of rope .................. 630-00 4. Friction of rope at curves ...... 176*44 Total 4,151-50 Ibs. USE OF THE FORMULA. 149 The speed is 4 miles an hour, which is 352 feet per minute. The horse-power therefore by formula (49) is : 4,151^352 =44 2o i x 33000 Allowing an efficiency of 50%, the hauling engine would have to be of about 90 horse-power. Answer. 90 indicated horse-power. The conditions would be fulfilled by a non-condensing engine with two cylinders 14" diameter x 2' 4-' stroke, running at 75 revolutions, with 30 Ibs. of steam, geared 3 to i to two drums, 4' 6" diameter by 2' wide. (20.) It is proposed to increase the quantity of air circu- lating round a mine, 10,000 cubic feet per minute, by build- ing a chimney (or cupola, as it is called in the North of England) on to the upcast shaft. The original volume is 60,000 cubic feet, and the upcast shaft is 400 feet in depth. What must be the height of the cupola ? The ratio the required volume bears to the volume circu- lating is 7' 000 = L. Therefore by formula (160) we 60,000 6 have : H = (7 X 7 _ !\ x 400 = 0-36 x 400 = 144. \6x6 ) Answer. 144 feet. (21.) What size of pipe would be required to supply an engine to be placed 1,200 yards from the boilers with 2 cubic feet per second of steam at a pressure of 30 Ibs. above the atmosphere, the pressure in the boilers being 45 Ibs. above the atmosphere ? First approximation : Let us assume that one cubic foot per second will be lost by condensation ; then, in order to deliver two cubic feet at the engine, the boilers must supply three cubic feet; and the mean volume squared passing through the pipe will be, by formula (100), EXAMPLES OF THE and the size of pipe to pass this quantity of steam, with the loss of pressure we can afford, viz., 15 Ibs., will be got from formula (99) as follows : a _ 1,000,000 (45-3) =958- 1, 200 X 6-333 X 2'06 and by Table XXI. this value of a corresponds with a pipe very nearly 3 inches in diameter. We must now find the loss by condensation with a 3 inch pipe. Its external diameter would be 3! inches, and if coated with ij inches of non-conducting material, the total outside diameter would be 6 J inches ; and the surface in square feet of a 6^-inch pipe, 1,200 yards long, is : 6*1; x ri4i6 x 1,200 x 3 = 6,120 square ft. The differences in temperature between the surface of the pipe, and the air in the drift, and the drift sides, will depend upon the non-conducting composition used, the depth of the pit, and the nature of the drift. We will assume that the drift is rather a small dry return without much air pass- ing, and that the pit is a shallow one. In this case we might suppose that : Temperature of pipe surface = 120 do. air in drift = 82 do. drift sides = 80 Then by formula (89 & 92) we have U = 74x40 x 6,126 x 1-28 =232.102 U! = 38x 1-14 x -5154x6,126 = 136,775 Total units of heat lost . =368,877 and the mean pressure of the steam being 37 \ Ibs. above the atmosphere, we have by formula (90) and Table XVI. : 368,877 I*" - = 403*14 Ibs. of steam condensed per hour. But one cubic ft. of steam, at a total pressure of 52 \ Ibs., weighs, by Table XVI., 2*05 oz. = 0-128 Ibs.; so that the Steam Boilers. A TREATISE ON STEAM BOILERS: Their Strength, Con- struction, and Economical Working. By ROBERT WILSON, C.E. Fifth Edition. i2mo, 6s. cloth. "The best treatise that has ever been published on steam boilers." Engineer. "The author shows himself perfect master of his subject, and we heartily recommend all em- ploying steam power to possess themselves of the work," Ryland's Iron Trade Circular. toiler Making. 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PRACTICAL RULES ON DRAWING, for the Operative Builder and Young Student in Architecture. By GEORGE PYNE. With 14 Plates, 4to, 75. 6d. boards. Civil Architecture. THE DECORATIVE PART OF CIVIL ARCHITECTURE. By Sir WILLIAM CHAMBERS, F.R.S. With Illustrations, Notes, and an Examination of Grecian Architecture, by JOSEPH GWILT, F.S.A. Edited by W. H. LEEDS. 66 Plates, 4to, 2is. cloth. 'Xhe House-Owner's Estimator. THE HOUSE-OWNER'S ESTIMATOR ; or, What will it Cost ito Build, Alter, or Repair? A Price Book adapted to the Use of Unpro- fessional People, as well as for the Architectural Surveyor and Builder. By Tthe late JAMES D. SIMON, A.R.I.B.A. Edited and Revised by FRANCIS T. W. MILLER, A.R.I.B.A. With numerous Illustrations. Third Edition, Revised. Crown 8vo, 35. 6d. cloth. "In two years it will repay its cost a hundred times over." Field* " A very handy book." English Mechanic. _ 12 CROSBY LOCKWOOD & CO.' S CATALOGUE. Designing, Measuring, and Valuing. THE STUDENT'S GUIDE to the PRACTICE of MEASUR- ING AND VALUING ARTIFICERS' WORKS. Containing Directions for taking Dimensions, Abstracting the .same, and bringing the Quantities into Bill, with Tables of Constants, and copious Memoranda lor the Valuation of Labour and Materials in the respective Trades of Bricklayer and Slater, Carpenter and Joiner, Painter and Glazier, Paperhanger, &c. With 8 Plates and 63 Woodcuts. Originally edited by EDWARD DOBSON, Architect. Fifth Edition, Revised, with considerable Additions on Mensuration and Construc- tion, and a New Chapter on Dilapidations, Repairs, and Contracts, by E. WYNDHAM TARN, M.A. Crown 8vo, gs. cloth. " Well fulfils the promise of its title-page, and we can thoroughly recommend it to the class for whose use it has been compiled. Mr. Tarn's additions and revisions have much increased the usefulness of the work, and have especially augmented its value to students." Engineering. "The work has been carefully revised and edited by Mr. E. Wyndham Tarn, M.A., and com- prises several valuable additions on construction, mensuration, dilapidations and repairs, and other matters. . . . This edition will be found the most complete treatise on the principles of measur- ing and valuing artificers' work that has yet been published." Building News. Pocket Estimator. THE POCKET ESTIMATOR for the BUILDING TRADES. Being an Easy Method of Estimating the various parts of a Building collec- tively, more especially applied to Carpenters' and Joiners' work. By A. C. BEATON, Author of "Quantities and Measurements." Third Edition, care- fully revised, 33 Woodcuts, leather, waistcoat-pocket size, is. 6d. "Contains a good deal of information not easily to be obtained from the ordinary price books. The prices .jiven are accurate, and up to date." Building News. Builder's and Surveyor's Pocket Technical Guide* THE POCKET TECHNICAL GUIDE AND MEASURER FOR BUILDERS AND SURVEYORS. Containing a Complete Explana- tion of the Terms used in Building Construction, Memoranda for Reference, Technical Directions for Measuring Work in all the Building Trades, with a Treatise on the Measurement of Timber, Complete Specifications, &c. &c. By A. C. BEATON. Second Edition, with 19 Woodcuts, leather, waistcoat- pocket size, is. 6d. "An exceedingly handy pocket companion, thoroughly reliable." Builder's Weekly Reporter. " This neat little compendium contains all that is requisite in carrying out contracts for ex- cavating, tiling, bricklaying, paving, &c." British Trade Journal. Donaldson on Specifications. THE HANDBOOK OF SPECIFICATIONS; or, Practical Guide to the Architect, Engineer, Surveyor, and Builder, in drawing up Specifications and Contracts for Works and Constructions. Illustrated by Precedents of Buildings actually executed by eminent Architects and En- gineers. By Professor T. L. DONALDSON, P.R.I. B.A., &c. New Edition, in One large Vol., 8vo, with upwards of 1,000 pages of Text, and 33 Plates, i us. 6d. cloth. " In this work forty-four specifications of executed works are given, including the specifica- tions for parts of the new Houses of Parliament, by Sir Charles Barry, and for the new Royal Exchange, by Mr. Tite, M.P. The latter, in particular, is a very complete and remarkable document. It embodies, to a great extent, as Mr. Donaldson mentions, 'the bill of quantities with the description of the works.' ... It is valuable as a record, and more valuable still as a book of precedents. . . . Suffice it to say that Donaldson's ' Handbook of Specifications ' must be bought by all architects." Builder. Bartholomeiv and Rogers' Specifications. SPECIFICATIONS FOR PRACTICAL ARCHITECTURE: A Guide to the Architect, Engineer, Surveyor, and Builder; with an Essay on the Structure and Science of Modern Buildings. Upon the Basis of the Work by ALFRED BARTHOLOMEW, thoroughly Revised, Corrected, and greatly added to by FREDERICK ROGERS, Architect. Second Edition, Revised, with Additions. With numerous Illusts., medium 8vo, 155. cloth. \_Just published* " The collection of specifications prepared by Mr. Rogers on the basis of Bartholomew's work is too well known to need any recommendation from us. It is one of the books with which every young architect must be equipped ; for time has shown that the specifications cannot be set aside through any defect in them." Architect. " Good forms for specifications are of cousiderable value, and it was an excellent idea to com- pile a work on the subject upon the basis of the late Alfred Bartholomew's valuable work. The second edition of Mr. Rogers's book is evidence of the want of a book dealing with modern ier- quirements and materials." Building News. DECORATIVE ARTS, etc. 13 DECORATIVE ARTS, etc. Woods and Marbles (Imitation of). SCHOOL OF PAINTING FOR THE IMITATION OF WOODS AND MARBLES, as Taught and Practised by A. R. VAN DER BURG and P. VAN DER BURG, Directors of the Rotterdam Painting Institution. Second and Cheaper Edition. Royal folio, i8 by 12^ in., Illustrated with 24 full-size Co- loured Plates ; also 12 plain Plates, comprising 154 Figures, price i us. 6d. List of Contents Introductory Chapter Tools required for Methods of Working Yellow Sienna Marble : Wood Painting Observations on the different Process of Working Juniper : Characteristics species of Wood: Walnut Observations on of the Natural Wood: Method of Imitation- Marble in general Tools required for Marble Vert de Mer Marble : Description of the Mar- Painting St. Remi Marble : Preparation of the I ble : Process of Working Oak : Description of Paints : Process of Working Wood Graining : the varieties of Oak : Manipulation of Oak- Preparation of Stiff and Flat Brushes : Sketch- painting : Tools employed : Method of Work- ing different Grains and Knots: Glazing of , ing Waulsort Marble: Varieties of the Marble: Wood Ash: Painting of Ash Breche (Brec- ! Process of Working The Painting of Iron with cia) Marble : Breche Violette : Process of Work- Red Lead: How to make Putty: Out-door ing Maple: Process of Working The different Work: Varnishing: Priming and Varnishing species of White Marble : Methods of Working : Woods and Marbles : Painting in General : Ceil- Painting White Marble with Lac-dye : Painting ings and Walls : Gilding : Transparencies, Flags, White Marble with Poppy-paint Mahogany : &c. List of Plates. i. Various Tools required for Wood Painting 2, 3. Walnut : Preliminary Stages of Graining and Finished Specimen 4. Tools used for Marble Painting and Method of Manipulation 5, 6. St. Remi Marble : Earlier Operations and Finished Specimen 7. Methods of Sketching different Grains, Knots, &c. 8. 9. Ash: Pre- " 'shed Specimen 10. liminary Stages and Finished Methods of Sketching Marble Grains i , ___ Breche Marble : Preliminary Stages of Working and Finished Specimen 13. Maple : Methods of Producing the different Grains 14, 15. Bird's- Finished Specimen of various G ecimen 19. Mahogany : Specimens rains and Methods of Manipulation . :. Mahogany: Earlier Stages and Finished Specimen 22, 23, 24. Sienna Marble : Varieties of Grain, Preliminary Stages and Finished Specimen 25, 26, 27. Juniper Wood : Methods of producing Grain, &c. : Preliminary Stages and Finished Specimen 28, 29, 30. Vert de Mer Marble : Varieties of Grain and Methods of Working Unfinished and Finished Speci- mens 31. 32. 33. Oak : Varieties of Grain, Tools .. 15. Bird's- - ' ' ; " ' eye Maple: Preliminary Stages and Finished Specimen 16. Methods of Sketching the dif- ferent Species of White Marble 17, 18. White ns 31. 32. 33. Oak : Varieties Employed, and Methods of Manipulation, Pre- liminary Stages and Finished Specimen 34, 35, 36. Waulsort Marble: Varieties of Grain, Un- finished and Finished Specimens. Marble : Preliminary Stages of Process and "Those who desire to attain skill in the art of painting woods and marbles, will find advantage in consulting this book. . . . Some of the Working Men's Clubs should give their young men the opportunity to study it." Ruilder. " A comprehensive guide to the art. The explanations of the processes, the manipulation and management of the colours, and the beautifully executed plates will not be the least valuable to the student who aims at making his work a faithful transcript of nature." Building News. Colour. A GRAMMAR OF COLOURING. Applied to Decorative Painting and the Arts. By GEORGE FIELD. New Edition, adapted to the use of the Ornamental Painter and Designer. By ELLIS A. DAVIDSON. With New Coloured Diagrams and Engravings. i2mo, 3$. 6d. cloth boards. "The book is a most useful resume of the properties of pigments." Builder. House Decoration. ELEMENTARY DECORATION. A Guide to the Simpler Forms of Everyday Art, as applied to the Interior and Exterior Decoration of Dwelling Houses, &c. By JAMES W. FACEY. With 68 Cuts. 2s. cloth limp. " As a technical guide-book to the decorative painter it will be found reliable." Building News , *** By the same Author, just published. PRACTICAL HOUSE DECORATION : A Guide to the Art of Ornamental Painting, the Arrangement of Colours in Apartments, and the principles of Decorative Design. With some Remarks upon the Nature and Properties of Pigments. With numerous Illustrations. i2mo, zs. 6d. cl. limp N.B. The above Two Works together in One Vol., strongly half-bound, 55. House Painting, etc. HOUSE PAINTING, GRAINING, MARBLING, AND SIGN WRITING, A Practical Manual of. By ELLIS A. DAVIDSON. Fourth Edition. With Coloured Plates and Wood Engravings. I2mo, 6s. cloth boards. A mass of information, of use to the amateur and of value to the practical man." English Mechanic. 14 CROSBY LOCK WOOD &> CO. '5 CATALOGUE. DELAMOTTES' WORKS on ILLUMINATION & ALPHABETS. A PRIMER OF THE ART OF ILLUMINATION, for the Use of Beginners : with a Rudimentary Treatise on the Art, Practical Directions for its exercise, and Examples taken from Illuminated MSS., printed in Gold and Colours. By F. DELAMOTTE. New and cheaper edition. Small 4to, 6s. orna- mental boards. ". . . . The examples of ancient MSS. recommended to the student, which, with much good sense, the author chooses from collections accessible to all, are selected with judgment and 1 knowledge, as well as \as>te"Athena:um. ORNAMENTAL ALPHABETS, Ancient and Medieval, from the Eighth Century, with Numerals; including Gothic, Church-Text, large and small, German, Italian, Arabesque, Initials for Illumination, Monograms Crosses, &c. &c., for the use of Architectural and Engineering Draughtsmen, Missal Painters, Masons, Decorative Painters, Lithographers, Engravers,. Carvers, &c, &c. Collected and Engraved by F. DELAMOTTE, and printed in Colours. New and Cheaper Edition. Royal 8vo, oblong, zs. 6d. ornamental boards. ' For those who insert enamelled sentences round gilded chalices, who blazon shop legends over shop-doors, who letter church walls with pithy sentences from the Decalogue, this book will be use- ful. "Atlienamm. EXAMPLES OF MODERN ALPHABETS, Plain and Ornamental; including German, Old English, Saxon, Italic, Perspective, Greek, Hebrew, Court Hand, Engrossing, Tuscan, Riband, Gothic, Rustic, and Arabesque with several Original Designs, and an Analysis of the Roman and Old English Alphabets, large and small, and Numerals, for the use of Draughtsmen, Sur- veyors, Masons, Decorative Painters, Lithographers, Engravers, Carvers, &c. Collected and Engraved by F. DELAMOTTE, and printed in Colours. New and Cheaper Edition. Royal 8vo, oblong, zs. 6d. ornamental boards. " There is comprised in it every possible shape into which the letters of the alphabet and numerals can be formed, and the talent which has been expended in the conception of the various plain and ornamental letters is wonderful." Standard. MEDIEVAL ALPHABETS AND INITIALS FOR ILLUMI- NA TORS. By F. G. DELAMOTTE. Containing 21 Plates and Illuminated Title, printed in Gold and Colours. With an Introduction by J. WILLIS BROOKS. Fourth and cheaper edition. Small 4to, 45. ornamental boards. ' ' A volume in which the letters of the alphabet come forth glorified in gilding and all the colours of the prism interwoven and intertwined and intermingled." Sun. THE EMBROIDERER'S BOOK OF DESIGN. Containing Initials, Emblems, Cyphers, Monograms, Ornamental Borders, Ecclesiastical Devices, Mediaeval and Modern Alphabets, and National Emblems. Col- lected by F. DELAMOTTE, and printed in Colours. Oblong royal 8vo, is. 6d., ornamental wrapper. "The book will be of great assistance to ladies and young children who are endowed with the art of plying the needle in this most ornamental and useful pretty work." East Anglian Times. Wood Carving. INSTRUCTIONS IN WOOD-CARVING, for Amateurs; with Hints on Design. By A LADY. With Ten large Plates, zs. 6d. in emblematic wrapper. "The handicraft of the wood-carver, so well as a book can impart it, may be learnt from ' A Lady's ' publication." Athencntm. " The directions given are plain and easily understood." English Mechanic. Glass Painting. GLASS STAINING AND THE ART OF PAINTING ON GLASS. From the German of Dr. GESSERT and EMANUEL OTTO FROMBERG. With an Appendix on THE ART OF ENAMELLING, izmo, zs. 6d. cloth limp. Letter Painting. THE ART OF LETTER PAINTING MADE EASY. By {AMES GREIG BADENOCH. With 12 full- page Engravings of Examples, is. cloth imp. "The system is a simple one, but quite original, and well worth the careful attention of letter- painters. It can be easily mastered and remembered." Building News. CARPENTRY, TIMBER, etc. 15 CARPENTRY, TIMBER, etc. Tredgold's Carpentry, partly He-written and En- larged by Tarn. THE ELEMENTARY PRINCIPLES OF CARPENTRY. A Treatise on the Pressure and Equilibrium of Timber Framing, the Resist- ance of Timber, and the Construction of Floors, Arches, Bridges, Roofs, Uniting Iron and Stone with Timber, &c. To which is added an Essay on the Nature and Properties of Timber, &c., with Descriptions of the kinds of Wood used in Building ; also numerous Tables of the Scantlings of Tim- ber for different purposes, the Specific Gravities of Materials, &c. By THOMAS TREDGOLD, C.E. With an Appendix of Specimens of Various Roofs of Iron and Stone, Illustrated. Seventh Edition, thoroughly revised and considerably enlarged by E. WYNDHAM TARN, M.A., Author of "The Science of Build- ing," &c. With 61 Plates, Portrait of the Author, and several Woodcuts. In> one large vol., 4to, price i 53. cloth. [Just published. "Ought to be in every architect's and every builder's library." Builder. " A work whose monumental excellence must commend it wherever skilful carpentry is con- cerned. The author's principles are rather confirmed than impaired by time. The additional plates are of great intrinsic value." Building News. Woodworking Machinery. WOODWORKING MACHINERY : Its Rise, Progress, and Con- struction. With Hints on the Management of Saw Mills and the Economical Conversion of Timber. Illustrated with Examples of Recent Designs by leading English, French, and American Engineers. By M. Powis BALE, A.M. Inst. C.E., M.I.M.E. Large crown 8vo, I2S. 6d. cloth. " Mr. Bale is evidently an expert on the subject, and he has collected so much information that his book is all-sufficient for builders and others engaged in the conversion of timber." Architect. "The most comprehensive compendium of wood- working machinery we have seen. The author is a thorough master of his subject." Building- News. " The appearance of this book at the present time will, we should think, give a considerable impetus to the onward march of the machinist engaged in the designing and manufacture of wood-working machines. It should be in the office of every wood-working factory.". English' Mechanic. Saw Mills. SAW MILLS: Their Arrangement and Management, and the Economical Conversion of Timber. (Being a Companion Volume to " Wood- working Machinery.") By M. Powis BALE, A.M. Inst. C.E., M.I.M.E. With numerous Illustrations. Crown 8vo, IDS. 6d. cloth. "The author is favourably known by his former work on '"Woodworking Machinery,' ofwhich we were able to speak approvingly. This is a companion volume, in-.which the administration of a large sawing establishment is discussed, and the subject examined from a financial standpoint Hence the size, shape, order, and disposition of saw-mills and the like are gone into in detail* and the course of the timber is traced from its reception to its delivery in its converted state. We could not desire a more complete or practical treatise." Builder. "We highly recommend Mr. Bale's work to the attention and perusal of all those who are en- gaged in the art of wood conversion, or who are about building or remodelling saw-mills on im- proved principles." Building News. Carpentering. THE CARPENTER'S NEW G UIDE ; or, Book of Lines for Car- penters ; comprising all the Elementary Principles essential for acquiring a knowledge of Carpentry. Founded on the late PETER NICHOLSON'S Standard Work. A New Edition, revised by ARTHUR ASHPITEL, F.S.A. Together with Practical Rules on Drawing, by GEORGE PYNE. With 74 Plates,. 4to, 1 is. cloth. Handrailing. A PRACTICAL TREATISE ON HANDRAILING : Showing Circular Work. CIRCULAR WORK IN CARPENTRY AND JOINERY: A Practical Treatise on Circular Work of Single and Double Curvature. By GEORGE COLLINGS, Author of " A Practical Treatise on Handrailing." Illus- trated with numerous Diagrams. i2mo, zs. 6d. cloth limp. {Just published,. 16 CROSBY LOCKWOOD &- CO.' S CATALOGUE. Timber Merchant's Companion. THE TIMBER MERCHANT'S AND BUILDER'S COM- PANION. Containing New and Copious Tables of the Reduced Weight and Measurement of Deals and Battens, of all sizes, from One to a Thousand Pieces, and the relative Price that each size bears per Lineal Foot to any given Price per Petersburg Standard Hundred ; the Price per Cube Foot of Square Timber to any given Price per Load of 50 Feet ; the proportionate Value of Deals and Battens by the Standard, to Square Timber by the Load of 50 Feet; the readiest mode of ascertaining the Price of Scantling per Lineal Foot of any size, to any given Figure per Cube Foot, &c. &c. By WILLIAM DOWSING. Third Edition, Revised and Corrected. Crown 8vo, 35. cloth. "Everything 1 is as concise and clear as it can possibly be made. There can be no doubt that very timber merchant and builder ought to possess it." Hull Advertiser. "An exceedingly well-arranged, clear, and concise manual of tables for the use of all who buy or sell timber." Journal of Forestry. Practical Timber Merchant. THE PRACTICAL TIMBER MERCHANT. Being a Guide for the use of Building Contractors, Surveyors, Builders, &c., comprising useful Tables for all purposes connected with the Timber Trade, Marks of Wood, Essay on the Strength of Timber, Remarks on the Growth of Timber, &c. By W. RICHARDSON. Fcap. 8vo, 35. 6d. cloth. " This handy manual contains much valuable information for the use of timber merchants, builders, foresters, and all others connected with the growth, sale, and manufacture of timber.' Journal of Forestry. Timber Freight Book. THE TIMBER MERCHANTS, SAW MILLER'S, AND IMPORTER'S FREIGHT BOOK AND ASSISTANT. Comprising Rules, Tables, and Memoranda relating to the Timber Trade. By WILLIAM RICHARDSON Timber Broker; together with a Chapter on " Speeds of Saw Mill Machinery," by M. Powis BALE, M.I.M.E., &c. i2mo, 35. 6d. cloth boards. "A very useful manual of rules, tables, and memoranda, relating to the timber trade. We re- commend it as a compendium of calculation to all timber measurers and merchants, and as supply- ing a real want in the trade." Building News. Tables for Packing-Case Makers. PACKING-CASE TABLES ; showing the number of Super- ficial Feet in Boxes or Packing-Cases, from six inches square and upwards. By W. RICHARDSON, Timber Broker. Oblong 4to, 35. 6d. cloth. " Invaluable labour-saving tables." Ironmonger "Will save much labour and calculation." Grocer. Superficial Measurement. THE TRADESMAN'S GUIDE TO SUPERFICIAL MEA- SUREMENT. Tables calculated from i to 200 inches in length, by i to 108 inches in breadth. For the use of Architects, Engineers, Timber Merchants, Builders,, &c. By JAMES HAWKINGS. Third Edition. Fcap., 35. 6d. cloth. " A useful collection of tables to facilitate rapid calculation of surfaces. The exact area of any surface of which the limits have been ascertained can be instantly determined. The book will be found of the greatest utility to all engaged in building operations." Scotsman, Forestry. THE ELEMENTS OF FORESTRY. Designed to afford In- formation concerning the Planting and Care of Forest Trees for Ornament or Profit, with Suggestions upon the Creation and Care of Woodlands. By F. B. HOUGH. Large crown 8vo, IDS. cloth. Timber Importer's Guide. THE TIMBER IMPORTER'S, TIMBER MERCHANT'S AND BUILDER'S STANDARD GUIDE. By RICHARD E. GRANDY. Compris- ing an Analysis of Deal Standards, Home and Foreign, with Comparative Values and Tabular Arrangements f-or fixing Nett Landed Cost on Baltic and North American Deals, including all intermediate Expenses, Freight, Insurance, &c. &c. Second Edition, carefully revised, izmo, 35. 6d. cloth. " Everything it pretends to be : built up gradually, it leads one from a forest to a treenail, and throws in, as a makeweight, a host of material concerning bricks, columns, cisterns, &c." English Mechanic. MINING AND MINING INDUSTRIES. 17 MINING AND MINING INDUSTRIES. Metalliferous Mining. BRITISH MINING : A Treatise on the History, Discovery, Practical Development, and Future Prospects of Metalliferous Mines in the United King- dom. By ROBERT HUNT, F.R.S., Keeper of Mining Records; Editor of " Ure's Dictionary of Arts, Manufactures, and Mines," &c. Upwards of 950 pp., with 230 Illustrations. Super-royal 8vo, 3 33. cloth. V s OPINIONS OF THE PRESS. "One of the most valuable works of reference of modern times. Mr. Hunt, as keeper of mining records of the United Kingdom, has had opportunities for such a task not enjoyed by anyone else, and has evidently made the most of them. . . . The language and style adopted are good, and the treatment of the various subjects laborious, conscientious, and scientific." Engineering. "Probably no one in this country was better qualified than Mr. Hunt for undertaking such a work. Brought into frequent and close association during a long life-time with the principal guar- dians of our mineral and metallurgical industries, he enjoyed a position exceptionally favourable for collecting the necessary information. The use which he has made of his opportunities is suffi- ciently attested by the dense mass of information crowded into the handsome volume which has just been published. ... In placing before the reader a sketch of the present position of British Mining, Mr. Hunt treats his subject so fully and illustrates it so amply that this section really forms a little treatise on practical mining. . . . The book is, in fact, a treasure-house of statistical information on mining subjects, and we know of no other work embodying so great a mass of matter of this kind. Were this the only merit of Mr. Hunt's volume it would be sufficient to render it indispensable in the library of everyone interested in the development of the mining and metallur- gical industries of this country." Athencenm. "A mass of information not elsewhere available, and of the greatest value to those who may be interested in our great mineral industries." Engineer. "A sound, business-like collection of interesting facts. . . . The amount of information Mr. Hunt has brought together is enormous. . . . The volume appears likely to convey more instruction upon the subject than any work hitherto published." Mining Journal. "The work will be for the mining industry what Dr. Percy's celebrated treatise has been for the metallurgical a book that cannot with advantage be omitted from the library." Iron and Coat Trades' Review. "The literature of mining has hitherto possessed no work approaching in importance to that which has just been published. There is much in Mr. Hunt's valuable work that every shareholder in a mine should read with close attention. The entire subject of practical mining from the first search for the lode to the latest stages of dressing the ore is dealt with in a masterly manner." Academy, Coal and Iron. THE COAL AND IRON INDUSTRIES OF THE UNITED KINGDOM. Comprising a Description of the Coal Fields, and of the Princi- pal Seams of Coal, with Returns of their Produce and its Distribution, and Analyses of Special Varieties. Also an Account of the occurrence of Iron Ores in Veins or Seams; Analyses of each Variety; and a History of the Rise and Progress of Pig Iron Manufacture since the year 1740, exhibiting the Economies introduced in the Blast Furnaces for its Production and Improve- ment. By RICHARD MEADE, Assistant Keeper of Mining Records. With Maps of the Coal Fields and Ironstone Deposits of the United Kingdom. 8vo, i 8s. cloth. "The book is one which must find a place on the shelves of all interested in coal and iron production, and in the iron, steel, and other metallurgical industries." Engineer, " Of this book we may unreservedly say that it is the best of its class which we have ever met. ... A book of reference which no one engaged in the iron or coal trades should omit from his library." Iron and Coal Trades' Review. "An exhaustive treatise and a valuable work of reference." Mining Journal. Prospecting. THE PROSPECTOR'S HANDBOOK: A Guide for the Pro- spector and Traveller in Search of Metal-Bearing or other Valuable Minerals. By J. W. ANDERSON, M.A. (Camb.), F.R.G.S., Author of "Fiji and New Caledonia." Small crown 8vo, 35. 6d. cloth. [Just published. "Will supply a much felt want, especially among Colonists, in whose way are so often thrown many mineralogical specimens, the value of which it is difficult for anyone, not a specialist, to determine. The author has placed his instructions before his readers in the plainest possible terms, and his book is the best of its kind." Engineer. "How to find commercial minerals, and how to identify them when they are found, are the leading points to which attention is directed. The author has managed to pack as much practical detail into his pages as would supply material for a book three times its size." Mining journal. " Those toilers who explore the trodden or untrodden tracks on the face of the globelwill find much that is useful to them in this \>Q<$a."Athtnaum. C 1 8 CROSBY LOCK WOOD & CO.' S CATALOGUE. Metalliferous Minerals and Mining. TREATISE ON METALLIFEROUS MINERALS AND MINING. By D. C. DAVIES, F.G.S., Mining Engineer, &c., Author of "A Treatise on Slate and Slate Quarrying." Illustrated with numerous Wood Engravings. Second Edition, carefully Revised. Crown 8vo, ias. 6d. cloth. "Neither the practical miner nor the general reader interested in mines, can have a better book for his companion and his guide." Mining Journal. "The volume is one which no student of mineralogy should be without." Colliery Guardian' " We are doing our readers a service in calling their attention to this valuable work." Mining- JJ'orld. " A book that will not only be useful to the geologist, the practical miner, and the metallurgist . but also very interesting to the general public." Iron. "As a history of the present state of mining throughout the world this book has a real valse, and it supplies an actual want, for no such information has hitherto been brought together within such limited space." Athenceum. Earthy Minerals and Mining. A TREATISE ON EARTHY AND OTHER MINERALS AND MINING. By D. C. DAVIES, F.G.S. Uniform with, and forming a Companion Volume to, the same Author's " Metalliferous Minerals and Mining." With 76 Wood Engravings. Crown 8vo, izs. 6d. cloth. " It is essentially a practical work, intended primarily for the use of practical men. . . . We do not remember to have met with any English work on mining matters that contains the same amount of information packed in equally convenient form." Academy. ' The book is clearly the result of many years' careful work and thought, and we should be nclined to rank it as among tbe very best of the handy technical and trades manuals which have recently appeared." British Quarterly Review. "The subject matter of the volume will be found of high value by all and they are a numer- ous class who trade in earthy minerals." Athenceum. "Will be found of permanent value for information and reference." Iron. Underground Pumping Machinery. MINE DRAINAGE. Being a Complete and Practical Treatise on Direct-Acting Underground Steam Pumping Machinery, with a Descrip- tion of a large number of the best known Engines, their General Utility and the Special Sphere of their Action, the Mode of their Application, and their merits compared with other forms of Pumping Machinery. By STEPHEN MICHELL. 8vo, 155. cloth. nd students f mines. It pumping machinery." Colliery Guardian. " Much valuable information is given, so that the book is thoroughly worthy of an extensive circulation amongst practical men and purchasers of machinery." Mining- Journal. Mining Tools. A MANUAL OF MINING TOOLS. For the Use of Mine Managers, Agents, Students, &c. By WILLIAM MORGANS, Lecturer on Prac- tical Mining at the Bristol School of Mines. i2mo, 35. cloth boards. ATLAS OF ENGRAVINGS to Illustrate the above, contain- ing 235 Illustrations of Mining Tools, drawn to scale. 4to, 6s. cloth boards. " Students in the science of mining, and overmen, captains, managers, and viewers may gain practical knowledge and useful hints by the study of Mr. Morgans' manual." Colliery Guardian. " A valuable work, which will tend materially to improve our mining literature." Mining Journal. Coal Mining. COAL AND COAL MINING: A Rudimentary Treatise on. By WARINGTON W. SMYTH, M.A., F.R.S., &c., Chief Inspector of the Mines of the Crown. New Edition, Revised and Corrected. With numerous Illustra- tions. I2mo, 45. cloth boards. "As an outline is given of every known coal-field in this and other countries, as well as of the principal methods of working, the book will doubtless interest a very large number of readers." Mining Journal. Subterraneous Surveying. SUBTERRANEOUS SURVEYING, Elementary and Practical Treatise on; with and without the Magnetic Needle. By THOMAS FENWICK, Surveyor of Mines, and THOMAS BAKER, C.E. izmo, 35. cloth boards. "Will be highly esteemed by colliery owners and lessees, mining engineers, a generally who require to be acquainted with the best means of securing the drainage of is a most valuable work, and stands almost alone in the literature of steam pumping ma NAVAL ARCHITECTURE, NAVIGATION, etc. 19 NAVAL ARCHITECTURE, NAVIGATION, etc. Chain Cables. CHAIN CABLES AND CHAINS. Comprising Sizes and Curves of Links, Studs, &c., Iron for Cables and Chains, Chain Cable and Chain Making, Forming and Welding Links, Strength of Cables and Chains, Certificates for Cables, Marking Cables, Prices of Chain Cables and Chains, Historical Notes, Acts of Parliament, Statutory Tests, Charges for Testing, List of Manufacturers of Cables, &c., &c. By THOMAS W. TRAILL, F.E.R.N., M. Inst. C.E.,the Engineer Surveyor in Chief, Board of Trade, the Inspector of Chain Cable and Anchor Proving Establishments, and General Superin- tendent, Lloyd's Committee on Proving Establishments. With numerous Tables, Illustrations and Lithographic Drawings. Folio, 2 2s. cloth, bevelled boards. " The author writes not only with a full acquaintance with scientific formute and details, but also with a profound and fully-instructed sense of the importance to the safety of our ships and sailors of fidelity in the manufacture of cables. We heartily recommend the book to the specialists to whom it is addressed." Atheneewn. " It contains a vast amount of valuable information. Nothing seems to be wanting to make it a complete and standard work of reference on the subject." Nautical Magazine. FocJtet-Book for Naval Architects and Shipbuilders. THE NAVAL ARCHITECT'S AND SHIPBUILDER'S POCKET-BOOK of Formula:, Rules, and Tables, and Marine Engineer's and Surveyor's Handy Book of Reference. By CLEMENT MACKROW, Member of the Institution of Naval Architects, Naval Draughtsman. Third Edition, Re- vised. With numerous Diagrams, &c. Fcap., zas. 6d, strongly bound in leather. "Should be used by all who are engaged in the construction or design of vessels. . . . Will be found to contain the most useful tables and formulae required by shipbuilders, carefully collected from the best authorities, and put together in a popular and simple form." Engineer. " The professional shipbuilder has now, in a convenient and accessible form, reliable data for solving many of the numerous problems that present themselves in the course of his work." Iron. "There is scarcely a subject on which a naval architect or shipbuilder can require to refresh his memory which will not be found within the covers of Mr. Mackrow's book." English Mechanic. or Marine Engineers. A POCKET-BOOK OF USEFUL TABLES AND FOR- MULAE FOR MARINE ENGINEERS. By FRANK PROCTOR, A.I.N.A Third Edition. Royal samo, leather, gilt edges, with strap, 45. "We recommend it to our readers as going far to supply a long-felt want." Naval Science. "A most useful companion to all marine engineers." United Service Gazette. Lighthouses. EUROPEAN LIGHTHOUSE SYSTEMS. Being a Report of a Tour of Inspection made in 1873. By Major GEORGE H. ELLIOT, Corps ot Engineers, U.S.A. With 51 Engravings and 31 Woodcuts. 8vo,2is. cloth. - \* The following are published in WEALE'S RUDIMENTARY SERIES. MASTING, MAST-MAKING, AND RIGGING OF SHIPS. By ROBERT KIPPING, N.A. Fifteenth Edition. i2mo, zs. 6d. cloth boards. SAILS AND SAIL-MAKING. Eleventh Edition, Enlarged, with an Appendix. By ROBERT KIPPING, N.A. Illustrated, izmo, 35. cloth boards. NAVAL ARCHITECTURE. By JAMES PEAKE. Fifth Edition with Plates and Diagrams. i2mo, 45. cloth boards. MARINE ENGINES AND STEAM VESSELS (A Treatise on). By ROBERT MURRAY, C.E., Principal Officer to the Board of Trade for the East Coast of Scotland District. Eighth Edition, thoroughly Revised, with considerable Additions, by the Author and by GEORGE CARLISLE, C.E., Senior Surveyor to the Board of Trade at Liverpool. 12010, 55. cloth boards. PRACTICAL NAVIGATION. Consisting of the Sailor's Sea- Book, by JAMES GREENWOOD and W. H. ROSSER ; together with the requisite Mathematical and Nautical Tables for the Working of the Problems, by HENRY LAW, C.E., and Professor J. R. YOUNG. imo, 75., half-bounjd, 20 CROSBY LOCK WOOD & CO. 'S CATALOGUE. NATURAL PHILOSOPHY AND SCIENCE. Text Book of Electricity. THE STUDENT'S TEXT-BOOK OF ELECTRICITY. By HENRY M. NOAD, Ph.D., F.R.S., F.C.S. New Edition, carefully Revised, With an Introduction and Additional Chapters, by W. H. PREECE, M.I.C.E., Vice-President of the Society of Telegraph Engineers, &c. With 470 Illustra tions. Crown 8vo, 125. 6d. cloth. "The original plan of this book has been carefully adhered to so as to make it a reflex of the existing state of electrical science, adapted for students. . . . Discovery seems to have pro- gressed with marvellous strides ; nevertheless it has now apparently ceased, and practical applica- tions have commenced their career ; and it is to give a faithful account of these that this fresli edition of Dr. Noad's valuable text-book is launched forth." Extractfrom Introduction by IV. H. Preece, Esq. " We can recommend Dr. Noad's book for clear style, great range of subject, a good index, and a plethora of woodcuts. Such collections as the present are indispensable." Athenceum. "An admirable text-book for every student beginner or advanced of electricity.' Engineering. Dr. Noad's text-book has earned for itself the reputation of a truly scientific manual for tne student of electricity, and we gladly hail this new amended edition, which brings it once more to the front. Mr. Preece as reviser, with the assistance of Mr. H. R. Kempe and Mr. I. P. Edwards, has added all the practical results of recent invention and research to the admirable theoretical expositions of the author, so that the book is about as complete and advanced as it is possible for any book to be within the limits of a text-book." Telegraphic Journal. Electricity. A MANUAL OF ELECTRICITY: Including Galvanism, Mag- netiim, Dia-Magnetism, Electro-Dynamics, Magno-Electricity, and the Electric TeUgraph. By HENRY M. NOAD, Ph.D., F.R.S., F.C.S. Fourth Edition. With 500 Woodcuts. 8vo, i 45. cloth. "The accounts given of electricity and galvanism are not only complete in a scientific sense. but, which is a rarer thing, are popular and interesting." Lancet. "It is worthy of a place in the library of every public institution." Mining Journal. Electric Light. ELECTRIC LIGHT : Its Production and Use. Embodying Plain Directions for the Treatment of Voltaic Batteries, Electric Lamps, and Dynamo-Electric Machines. By J. W. URQUHART, C.E., Author of " Electro- plating: A Practical Handbook " Edited by F. C. WEBB, M.I.C.E., M.S.T.E. Second Edition, Revised, with large Additions and 128 Illusts. 75. 6d. cloth. " The book is by far the best that we have yet met with on the subject." Athenaum. "It is the only work at present available which gives, in language intelligible for the most part to the ordinary reader, a general but concise history of the means which have been adopted up to the present time in producing the electric light." Metropolitan Electric Lighting. THE ELEMENTARY PRINCIPLES OF ELECTRIC LIGHT- ING. By ALAN A. CAMPBELL SWINTON, Associate S.T.E. Crown 8vo, is. 6d., cloth. [Just published. " As a stepping-stone to treatises of a more advanced nature, this little work will be found most efficient." Bookseller. "Anyone who desires a short and thoroughly clear exposition of the elementary principles of electric-lighting cannot do better than read this little work." Bradford Observer. Dr. Lardner's School Handbooks. NATURAL PHILOSOPHY FOR SCHOOLS. By Dr. LARDNER. 328 Illustrations. Sixth Edition. One Vol., 35. 6d. cloth. " A very convenient class-book for junior students in private schools. It is intended to convey,. in clear and precise terms, general notions of all the principal divisions of Physical Science." British Quarterly Review. ANIMAL PHYSIOLOGY FOR SCHOOLS. By Dr. LARDNER. With 190 Illustrations. Second Edition. One Vol., 35. 6d. cloth. " Clearly written, well arranged, and excellently illustrated." Gardener's Chronicle. Dr. Lardner's Electric Telegraph. THE ELECTRIC TELEGRAPH. By Dr. LARDNER. Re- vised and Re- written by E. B. BRIGHT, F.R.A.S. 140 Illustrations. Small 8vo, 25. 6d. cloth. One of the most readable books extant on the Electric Telegraph." English Mechanic. NATURAL PHILOSOPHY AND SCIENCE. 21 Storms. STORMS : Their Nature, Classification, and Laws; with the Means of Predicting them by their Embodiments, the Clouds. By WILLIAM BLASIUS. With Coloured Plates and numerous Wood Engravings. Crown 8vo, IDS. 6d. cloth. " A useful repository to meteorologists in the study of atmospherical disturbances. Will repay perusal as being the production of one who gives evidence of acute observation." Nature. The Blowpipe. THE BLOWPIPE IN CHEMISTRY, MINERALOGY, AND GEOLOGY. Containing all known Methods of Anhydrous Analysis, many Working Examples, and Instructions for Making Apparatus. By Lieut.- Colonel W. A. Ross, R.A., F.G.S. With 120 Illustrations. Crown 8vo, 39. 6d. cloth. "The student who goes conscientiously through the course of experimentation here laid down yfll gain a better insight into inorganic chemistry and mineralogy than if he had 'got up 'any of tf-he best text-books 01 the day, and passed any number of examinations." Chetnicai News. The Military Sciences. AIDE-MEMOIRE TO THE MILITARY SCIENCES. Framed from Contributions of Officers and others connected with the different Ser- vices. Originally edited by a Committee of the Corps of Royal Engineers. Second Edition, most carefully revised by an Officer of the Corps, with many Additions ; containing nearly 350 Engravings and many hundred Woodcuts. Three Vols., royal 8vo, extra cloth boards, and lettered, 4 IDS. "A compendious encyclopxdia of military knowledge, to which we are greatly indebted." {.dinkurgh Review. " The most comprehensive work of reference to the military and collateral sciences.' Volun- teer Service Gazette. Field Fortification. A TREATISE ON FIELD FORTIFICATION, THE ATTACK OF FORTRESSES, MILITARY MINING, AND RECONNOITRING. By Colonel I. S. MACAULAY, late Professor of Fortification in the R.M.A., Wool- wich. Sixth Edition, crown 8vo, cloth, with separate Atlas of 12 Plates, I2S. Conchology. MANUAL OF THE MOLLUSC A : A Treatise on Recent and Fossil Shells. By Dr. S. P. WOODWARD, A.L.S. With Appendix by RALPH TATE, A.L.S., F.G.S. With numerous Plates and 300 Woodcuts. Cloth boards, 75. 6d. "A most valuable storehouse of conchological and geological information." Hard-wicke' s cience Gossip. A stronomy. ASTRONOMY. By the late Rev. ROBERT MAIN, M.A., F.R.S., formerly Radcliffe Observer at Oxford. Third Edition, Revised and Cor- rected to the present time, by WILLIAM THYNNE LYNN, B. A., F.R.A.S., formerly of the Royal Observatory, Greenwich, izmo, 2S. cloth limp. " A sound and simple treatise, carefully edited, and a capital book for beginners." Knowledge- "Accurately brought down to tne requirements of the present time." Educational Times RUDIMENTARY TREATISE ON GEOLOGY, PHYSICAL AND HISTORICAL. Consisting of "Physical Geology," which sets forth the leading Principles of the Science ; and " Historical Geology," which treats of the Mineral and Organic Conditions of the Earth at each successive epoch, especial reference being made to the British Series of Rocks. By RALPH TATE, A.L.S., F.G.S., &c., &c. With 250 Illustrations. I2mo, 55. cloth boards. " The fulness of the matter has elevated the book into a manual. Its information is exhaustive *nd well arranged." School Board Chronicle. Geology and Genesis. THE TWIN RECORDS OF CREATION; or, Geology and Genesis : their Perfect Harmony and Wonderful Concord. By GEORGE W. VICTOR LE VAUX. Numerous Illustrations. Fcap. 8vo, 55. cloth. "A valuable contribution to the evidences of revelation, and disposes very conclusively of the arguments of those who would set God's Works against God's Word. No real difficulty is shirked, and no sophistry is left unexposed." The Rock. 22 CROSBY LOCK WOOD 6- CO.'S CATALOGUE. Dr. LA ROGER'S HANDBOOKS of NATURAL PHILOSOPHY. *** The following five volumes, though each is complete in itself, and to be pur' chased separately, form A COMPLETE COURSE OF NATURAL PHILOSOPHY. The style is studiously popular. It has been the author's aim to supply Manuals for the Student, the Engineer, the Artisan, and the superior classes in Schools. THE HANDBOOK OF MECHANICS. Enlarged and almost re- written by BENJAMIN LOEWY, F.R.A.S. With 378 Illustrations. Post 8vo, 6s. cloth. "The perspicuity of the original has been retained, and chapters which had become obsolete have been replaced by others of more modern character. The explanations throughout are studiously popular, and care has been taken to show the application of the various branches o? physics to the industrial arts, and to the practical business of lite." Mining Journal. "Mr. Loewy has carefully revised the book, and brought it up to modern requirements." Nature. " Natural philosophy has had few exponents more able or better skilled in the art of popu- larising the subject than Dr. Lardner ; and Mr. Loewy is doing good service in fitting this treatise, and the others of the series, for use at the present time." Scotsman. THE HANDBOOK OF HYDROSTATICS AND PNEUMATICS. New Edition, Revised and Enlarged, by BENJAMIN LOEWY, F.R.A.S. With 236 Illustrations. Post 8vo, 55. cloth. "For those 'who desire to attain an accurate knowledge of physical science without the pro- found methods of mathematical investigation,' this work is not merely intended, but well adapted."' Chemical News. " The Tolume before us has been carefully edited, augmented to nearly twice the bulk of the former edition, and all the most recent matter has been added. . . . It is a valuable text-book." Nature. " Candidates for pass examinations will find it, we think, specially suited to their requirements." English Mechanic. THE HANDBOOK OF HEAT. Edited and almost entirely re- written by BENJAMIN LOEWY, F.R.A.S., &c. 117 Illustrations. Post 8vo, 6s- cloth. "The style is always clear and precise, and conveys instruction without leaving any cloudiness- or lurking doubts behind." Engineering. "A most exhaustive book on the subject on which it treats, and is so arranged that it can be understood by all who desire to attain an accurate knowledge of physical science Mr, Loewy has included all the latest discoveries in the varied laws and effects of heat." Standard. "A complete and handy text-book for the use of students and general readers." English Mechanic. THE HANDBOOK OF OPTICS. By DIONYSIUS LARDNER, D.C.L. formerly Professor of Natural Philosophy and Astronomy in University College, London. New Edition. Edited byT. OLVER HARDING, B.A. Lond. of University College, London. With 298 Illustrations. Small 8vo, 448- pages, 55. cloth. "Written by one of the ablest English scientific writers, beautifully and elaborately illustrated. 1 ' Mechanics' Magazine. THE HANDBOOK OF ELECTRICITY, MAGNETISM, AND ACOUSTICS. By Dr. LARDNER. Ninth Thousand. Edit, by GEORGE CAREY FOSTER, B.A., F.C.S. With 400 Illustrations. Small 8vo, 53. cloth. " The book could not have been entrusted to anyone better calculated to preserve the terse anc\ lucid style of Lardner, while correcting his errors and bringing up his work to the present state of scientific knowledge." Popular Science Review. Dr. Lardner's Handbook of Astronomy. THE HANDBOOK OF ASTRONOMY. Forming a Companion to the " Handbook of Natural Philosophy.'' By DIONYSIUS LARDNER, D.C.L. f formerly Professor of Natural Philosophy and Astronomy in University College, London. Fourth Edition. Revised and Edited by EDWIN DUNKIN, F.R.A.S., Royal Observatory, Greenwich. With 38 Plates and upwards of 100 Woodcuts. In One Vol., small 8vo, 550 pages, gs. 6d. cloth. "Probably no other book contains the same amount of information in so compendious and well- arranged a form certainly none at the price at which this is offered to the public.' Athenaum. "We can do no other than pronounce this work a most valuable manual of astronomy, and wa strongly recommend it to all who wish to acquire a general but at the same time correct acquaint- ance with this sublime science." Quarterly Journal of Science. "One of the most deservedly popular books on the subject . . . We would recommend nol only the student of the elementary principles of the science, but he who aims at mastering the- higher and mathematical branches of astronomy, not to be without this work beside him." Practi- cal Magazine. NATURAL PHILOSOPHY AND SCIENCE. 23 DR. LARDNER'S MUSEUM OF SCIENCE AND ART. THE MUSEUM OF SCIENCE AND ART. Edited by DIONYSIUS LARDNER, D.C.L., formerly Professor of Natural Philosophy and Astronomy in University College, London. With upwards of 1,200 Engrav- ings on Wood. In 6 Double Volumes, i is., in a new and elegant cloth bind- ing ; or handsomely bound in half-morocco, 31$. 6d. Contents: The Planets: Are they Inhabited Worlds t Weather Prognostics Popular Fallacies in Questions of Physical Science Latitudes and Longitudes Lunar Influences Meteeric Stones and Shooting Stars Railway Accidents Light Common Things : Air Locomotion in the United States Cometary Influences Comnnn Things: Water The Potter's Art- Common Things : Fire Locomotion and Transport, their Influence and Progress The Moon Common Things: The Earth The Electric Telegraph Terrestrial Heat The Sun Earthquakes and Volcanoes Barometer, Safety Lamp, and Whitworth's Micrometric Appantus Steam The Steam Engine The Eye The Atmosphere Time Common Things : Pumps Common Things : Spectacles, the Kaleidoscope Clocks and Watches motive Thermometer New Planets: Le- verrier and Adams's Planet Magnitude and Minuteness Common Things: The Almanack Optical Images How to observe the Heavens Images Common Things : The Looking-glass Stellar Universe The Tides Colour Com- mon Things: Man Magnifying Glasses In- stinct and Intelligence The Solar Microscope The Camera Lucida The Magic Lantern The Camera Obscura The Microscope The White Ants : Their Manners and Habits The Surface of the Earth, or First Notions of Geography Science and Poetry The Bee- Steam Navigation Electro-Motive Power Thunder, Lightning, and the Aurora Borealis The Printing Press The Crust of the Earth Comets The Stereoscope The Pre-Ada- mite Earth Eclipses Sound. Microscopic Drawing and Engraving Locc Opinions of the Press. "This series, besides affording popular but sound instruction on scientific subjects, with which the humblest; man in the country ought to be acquainted, also undertakes that teaching of ' Com- mon Things ' which every well-wisher of his kind is anxious to promote. Many thousand copies of this ssrviceable publication have been printed, in the belief and hope that the desire for instruction and improvement widely prevails ; and we have no fear that such enlightened faith will meet with disappointment." Times. J' A cheap and interesting publication, alike informing and attractive. The papers combine subjects of importance and great scientific knowledge, considerable inductive powers, and a popular style of treatment." Spectator. "The 'Museum of Science and Art' is the most valuable contribution that has ever been made to the Scientific Instruction of every class of society." Sir DAVID BREWSTER, in the North British Review. "Whether we consider the liberality and beauty of the illustrations, the charm of the writing, or ;he durable interest of the matter, we must express our belief that there is hardly to be found among the new books one that would be welcomed by people of so many ages and classes as a veluable present." Examiner. \* Separate books formed from the above, suitable for Workmen's Libraries, Science Classes, &c. Common Things Explained. Containing Air, Earth, Fire, Water, Time, Man, the Eye, Locomotion, Colour, Clocks and Watches, &c. 233 Illus- trations, cloth gilt, 55. The Microscope. Containing Optical Images, Magnifying Glasses, Origin and Description of the Microscope, Microscopic Objects, the Solar Micro- scope, Microscopic Drawing and Engraving, &c, 147 Illustrations, cloth gilt, 2S. Popular Geology. Containing Earthquakes and Volcanoes, the Crust ot the Earth, &c. 201 Illustrations, cloth gilt, zs. 6d. Popular sphere, Thermometer, the Barometer, Sound, &c. 85 Steam and its Uses. Including the Steam Engine, the Locomotive, and Steam Navigation. 89 Illustrations, cloth gilt, 25. Popular Astronomy. Containing How to observe the Heavens The Earth, Sun, Moon, Planets, Light, Comets, Eclipses, Astronomical Influ- ences, &c. 182 Illustrations, 45. 6d. The Bee and White Ants : Their Manners and Habits. With Illustra- tions of Animal Instinct and Intelligence. 135 Illustrations, cloth gilt, 2s. The Electric Telegraph Popularised. To render intelligible to all who can Read, irrespective of any previous Scientific Acquirements, the various forms of Telegraphy in Actual Operation. 100 Illustrations, cloth gilt, is. 6d. 24 CROSBY LOCKWOOD & CO.' S CATALOGUE. MATHEMATICS, GEOMETRY, TABLES, etc. Practical Mathematics. MATHEMATICS FOR PRACTICAL MEN. Being a Com- mon-place Book of Pure and Mixed Mathematics. Designed chiefly for the Use of Civil Engineers, Architects and Surveyors. By OLINTHUS GREG- ORY, LL.D., F.R.A.S., Enlarged by HENRY LAW, C.E. 4th Edition, care- fully Revised by J. R. YOUNG, formerly Professor of Mathematics, Belfast College. With 13 Plates, 8vo, i is. cloth. " The engineer or architect will here find ready to his hand rules for solving nearly every mathematical difficulty that may arise in his practice. The rules are in all cases explained by means of examples, in which every step of the process is clearly worked out." Bitilder. " One of the most serviceable books for practical mechanics. . . . It is an instructive book for the student, and a Text-book for him who, having once mastered the subjects it treats of, needs occasionally to refresh his memory upon them." Bitilding News. Metrical Units and Systems, etc. MODERN METROLOGY : A Manual of the Metrical Units and Systems of the Present Century. With an Appendix containing a proposed English System. By Lowis D'A. JACKSON, A.M. Inst. C.E., Author of "Aid to Survey Practice," &c. Large crown 8vo, 125. 6d. cloth. "The author has brought together much valuable and interesting information. . . . We cannot but recommend the work to the consideration of all interested in the practical reform of our weights and measures." Nature. " For exhaustive tables of equivalent weights and measures of all sorts, and for clear demonstra- tions of the effects of the various systems that have been proposed or adopted, Mr. Jackson's treatise is without a rival." Academy. The Metric System. A SERIES OF METRIC TABLES, in which the British Stard- ardMeasures and Weights are compared with those oftheMetric System atprestnt in Use on the Continent. By C. H. DOWLING, C.E. 8vo, IDS. 6d. strongly bound. "Their accuracy has been certified by Professor Airy, the Astronomer-Royal." Bitilder. "Mr. Bowling's Tables are well put together as a ready-reckoner for the conversion of one system into the other." Athenauin Geometry for the Architect) Engineer, etc. PRACTICAL GEOMETRY, for the Architect, Engineer and Mechanic. Giving Rules for the Delineation and Application of various Geometrical Lines, Figures and Curves. By E. W. TARN, M.A., Architect, Author of "The Science of Building," &c. Second Edition. With Appen- dices on Diagrams of Strains and Isometrical Projection. With 172 Illus- trations, demy 8vo, 95. cloth. " No book with the same objects in view has ever been published in which the clearness of the rules laid down and the illustrative diagrams have been so satisfactory." Scotsman. "This is a manual for the practical man, whether architect, engineer, or mechanic. . . . The object of the author being to avoid all abstruse formulae or complicated methods, and to enable persons with but a moderate knowledge of geometry to work out the problems required." English Mechanic. The Science of Geometry. THE GEOMETRY OF COMPASSES; or, Problems Resolved, by the mere Description of Circles and the use of Coloured Diagrams and Symbols. By OLIVER BYRNE. Coloured Plates. Crown 8vo, 35. 6d. cloth. " The treatise is a good one, and remarkable like all Mr. Byrne's contributions to the science of geometry for the lucid characte^ of its teaching." Building Nevis. Iron and Metal Trades 9 Calculator. THE IRON AND METAL TRADES' COMPANION. For expeditiously ascertaining the Value of any Goods bought or sold by Weight, from is. per cwt. to iizs. per cwt., and from one farthing per pound to one shilling per pound. Each Table extends from one pound to 100 tons. To which are appended Rules on Decimals, Square and Cube Root, Mensuration of Superficies and Solids, &c. ; Tables of Weights of Materials, and other Useful Memoranda. By THOS. DOWNIE. 396 pp., 95. Strongly bound leather. " A most useful set of tables, and will supply a want, for nothing like them before existed." " Although specially adapted to the iron and metal trades, the tables will be found useful in every other business in which merchandise is bought and sold by weight." Rail-way News. MATHEMATICS, GEOMETRY, TABLES, etc. 25 Calculator for Numbers and Weights Combined. THE COMBINED NUMBER AND WEIGHT CALCU- LA TOR. Containing upwards of 250,000 Separate Calculations, showing at a glance the value at 421 different rates, ranging from ^th f a Penny to 205. each, or per cwt., and 20 per ton, of any number of articles consecutively, from i to 470. Any number of cwts., qrs., and Ibs., from i cwt. to 470 cwts. Any number of tons, cwts., qrs., and Ibs., from i to 23^ tons. By WILLIAM CHADWICK, Public Accountant. Imp. 8vo, 305., strongly bound. t3T This comprehensive and entirely unique and original Calculator is adapted /ov the use of Accountants and Auditors, Railway Companies, Canal Companies, Shippers, Shipping Agents, General Carriers, &c. Ironfounders, Brass founders, Metal Merchants, Iron Manufacturers, Iron- mongers, Engineers, Machinists, Boiler Makers, Millwrights, Roofing, Bridge and 'Girder Makers, Colliery Proprietors, &c. Timber Merchants, Builders, Contractors, Architects, Surveyors, Auctioneers, Valuers, Brokers, Mill Owners and Manufacturers, Mill Furnishers, Merchants and General Wholesale Tradesmen. *** OPINIONS OF THE PRESS. "The book contains the answers to questions, and not simply a set of ingenious puzzle nethods of arriving at results. It is as easy of reference for any answer or any number ot answers as a dictionary, and the references are even more quickly made. For making up accounts or esti- jnates, the book must prove invaluable to all who have any considerable quantity of calculations involving price and measure in any combination to do." Engineer. "The most complete and practical ready reckoner which it has been our fortune yet to see. t is difficult to imagine a trade or occupation in which it could not be of the greatest use, either n saving human labour or in checking work. The publishers have placed within the reach of every commercial man an invaluable and unfailing assistant." The Miller, Comprehensive Weight Calculator. THE WEIGHT CALCULATOR. Being a Series of Table* upon a New and Comprehensive Plan, exhibiting at One Reference the exact Value of any Weight from i Ib. to 15 tons, at 300 Progressive Rates, from id. to i68s. per cwt., and containing 186,000 Direct Answers, which, with their Combinations, consisting of a single addition (mostly to be performed at sight), will afford an aggregate of 10,266,000 Answers ; the whole being calcu- lated and designed to ensure correctness and promote despatch. By HENRY HARBEN, Accountant. An entirely New Edition, carefully Revised. Royal 8vo, strongly half-bound, i 55. "Of priceless value to business men. Its accuracy and completeness have secured for it a reputation which renders it quite unnecessary for us to say one word in its praise. It is a necessary fofeok in all mercantile offices." Sheffield Independent. Comprehensive Discount Guide. THE DISCOUNT GUIDE. Comprising several Series of Tables for the use of Merchants, Manufacturers, Ironmongers, and others, by which may be ascertained the exact Profit arising from any mode of using Discounts, either in the Purchase or Sale of Goods, and the method of either Altering a Rate of Discount or Advancing a Price, so as to produce, by one operation, a sum that will realise any required profit after allowing one or more Discounts : to which are added Tables of Profit or Advance from ii to 90 per cent., Tables of Discount from i J to 98$ per cent., and Tables of Com- mission, &c., from fc to 10 per cent. By HENRY HARBEN, Accountant, Author of " The Weight Calculator." New Edition, carefully Revised and Corrected. Demy 8vo, 544 pp. half-bound, r 55. " A book such as this can only be appreciated by business men, to whom the saving of time cneans saving of money. We have the high authority of Professor J. R. Young that the tables throughout the work are constructed upon strictly accurate principles. The work must prove nf great yalue to merchants, manufacturers, and general traders." British Trade yournal Iron Shipbuilders 9 and Iron Merchants 9 Tables. IRON- PL ATE WEIGHT TABLES: For Iron Shipbuilders, Engineers and Iron Merchants. Containing the Calculated Weights of up- wards of 150,000 different sizes of Iron Plates, from i foot by 6 in. by i in. to 10 feet by 5 feet by i in. Worked out on the basis of 40 Ibs. to the square foot of Iron of i inch in thickness. Carefully compiled and thoroughly Re- vised by H. BURLINSON and W. H. SIMPSON. Oblong 4to, 255. half-bound. "This work will be found of great utility. The authors have had much practical experience of what is wanting in making estimates; and the use of the book will save much time hi making elaborate calculations." English Mechanic. 26 CROSBY LOCKWOOD &> CO.' S CATALOGUE INDUSTRIAL AND USEFUL ARTS. Soap-making. THE ART OF SOAP-MAKING : A Practical Handbook of the Manufacture of Hard and Soft Soaps, Toilet Soaps, &c. Including many New Processes, and a Chapter on the Recovery of Glycerine from Waste Leys. By ALEXANDER WATT, Author of "Electro-Metallurgy Practically Treated," &c. With numerous Illustrations. Second Edition, Revised. Crown 8vo, gs. cloth. "The work will prove very useful, not merely to the technological student, but to the practica soapboiler who wishes to understand the theory of his art." Chemical New s. "It is really an excellent example of a technical manual, entering, as it does, thoroughly and exhaustively both into the theory and practice of soap manufacture." Knowledge. "Mr. Watt's book is a thoroughly practical treatise on an art which has almost no literature in our language. We congratulate the author on the success of his endeavour to fill a void in English technical literature." Mature. Leather Manufacture. THE ART OF LEATHER MANUFACTURE. Being a Practical Handbook, in which the Operations of Tanning, Currying, and Leather Dressing are fully Described, and the Principles of Tanning Ex- plained, and many Recent Processes introduced; as also Methods for the Estimation of Tannin, and a Description of the Arts of Glue Boiling, Gut Dressing, &c. By ALEXANDER WATT, Author of " Soap-Making,' 1 " Electro- Metallurgy," &c. With numerous Illustrations. Crown 8vo, 12$. 6d. cloth. " Mr. Watt has rendered an important service to the trade, and no less to the student of technology." Chemical News. "A sound, comprehensive treatise. The book is an eminently valuable production which re- dounds to the credit of both author and publishers." Chemical Review. "This volume is technical without being tedious, comprehensive and complete without being prosy, and it bears on every page the impress of a master hand. We have never come across ai better trade treatise, nor one that so thoroughly supplied an absolute want." Shoe and Leather- Trades' Chronicle. Boot and Shoe Making. THE ART OF BOOT AND SHOE-MAKING. A Practical Handbook, including Measurement, Last-Fitting, Cutting-Out, Closing and Making, with a Description of the most approved Machinery employed. By JOHN B. LEND, late Editor of St. Crispin, and The Boot and Shoe-Maker. With numerous Illustrations. Crown 8vo, 55. cloth. " This excellent treatise is by far the best work ever written on the subject. A new work, embracing all modern improvements, was much wanted. This want is now satisfied. The chapter on clicking, which shows how waste may be prevented, will save fifty times the price of the book." Scottish Leather Trader. Dentistry. MECHANICAL DENTISTRY: A Practical Treatise on the Construction of the various kinds of Artificial Dentures. Comprising also Use- ful Formula?, Tables and Receipts for Gold Plate, Clasps, Solders, &c. &c. By CHARLES HUNTER. Second Edition, Revised. With upwards of 100 Wood Engravings. Crown 8vo, ys. 6d. cloth. " We can strongly recommend Mr. Hunter's treatise to all students preparing for the profession of dentistry, as well as to every mechanical dentist." Dublin Journal of Medical Science. "A work in a concise form that few could read without gaining information from." British Journal of Dental Science. brewing. A HANDBOOK FOR YOUNG BREWERS. By HERBERT EDWARDS WRIGHT, B.A. Crown 8vo, 35. 6d. cloth. " This little volume, containing such a large amount of good sense in so small a compass, o u ght to recommend itself to every brewery pupil, and many who have passed that stage." Brewers' Guardian. "The book is very clearly written, and the author has successfully brought his scientific know* ledge to bear upon the various processes and details of brewing." Brewer. Wood Engraving. A PRACTICAL MANUAL OF WOOD ENGRAVING. With a Brief Account of the History of the Art. By WILLIAM NORMAN BROWN. With numerous Illustrations. Crown 8vo, 25. cloth. " The author deals with the subject in a thoroughly practical and easy series of representative lessons." Paper and Printing Trades' Journal. INDUSTRIAL AND USEFUL ARTS. 27 Electrolysis of Gold, Silver, Copper, &c. ELECTRO-DEPOSITION : A Practical Treatise on the Electrolysis of Gold, Silver, Copper, Nickel, and other Metals and Alloys. With descrip- tions of Voltaic Batteries, Magnets and Dynamo-Electric Machines, Ther- mopiles, and of the Materials and Processes used in every Department of the Art, and several Chapters on ELECTRO-METALLURGY. By ALEX- ANDER WATT, Author of "Electro-Metallurgy," "The Art of Soapmaking." &c. With numerous Illustrations. Crown 8vo, I2s. 6d., cloth. " Evidently written by a practical man who has spent a long period of time in electro-plate workshops. The information given respecting the details of workshop manipulation is remarkably- complete. . . . Mr. Watt's book will prove of great value to electro-depositors, jewellers, and various other workers in metal." Nature. "Eminently a book for the practical worker in electro-deposition. It contains minute and< practical descriptions of methods, processes and materials as actually pursued and used in the- workshop. Mr. Watt's book recommends itself to all interested in its subjects. Engineer. "Contains an enormous quantity of practical information ; and there are probably few items, omitted which could be of any possible utility to workers in galvano-plasty. As a practical manual the book can be recommended to all who wish to study the art of electro-deposition." English Mechanic. Electroplating, etc. ELECTROPLATING : A Practical Handbook. By J. W. URQU- HART, C.E. With numerous Illustrations. Crown 8vo, 55. cloth. " The information given appears to be based on direct personal knowledge. . . Its science is sound and the style is always &&&[." Athenceum. Electrotyping, etc. ELECTROTYPING : The Reproduction and Multiplication of Print- ing Surfaces and Works of Art by the Electro-deposition of Metals. By J. W. URQUHART, C.E. Crown 8vo, 55. cloth. "The book is thoroughly practical. The reader is, therefore, conducted through the leading aws of electricity, then through the metals used by electrotypers, the apparatus, and the depositing.' processes, up to the final preparation of the work." Art Journal. We can recommend this treatise, not merely to amateurs, but to those actually engaged in the trade." Chemical News. Electro-Metallurgy. ELECTRO-MET A LL URG Y ; Practically Treated. By ALEXANDER WATT, F.R.S.S.A. Eighth Edition, Revised, with Additional Matter and Illustrations, including the most recent Processes. i2mo, 35. 6d. cloth boards. "From this book both amateur and artisan may learn everything necessary for the successful prosecution of electroplating." Iron. Goldsmiths' Work. THE GOLDSMITH'S HANDBOOK. By GEORGE E. GEE, Jeweller, &c. Third Edition, considerably Enlarged. izmo, 35. 6d. cloth boards. "A good, sound, technical educator, and will be generally accepted as an authority. It is. essentially a book for the workshop, and exactly fulfils the purpose intended." Horological Journal. "Will speedily become a standard book which few will care to be without." Jeweller and Metalworker. Silversmiths 9 Work. THE SILVERSMITH'S HANDBOOK. By GEORGE E. GEE,. Jeweller, &c. Second Edition, Revised, with numerous Illustrations, izmo 35. 6d. cloth boards. "The chief merit of the work is its practical character. . . The workers in the trade will speedily discover its merits when they sit down to study it." English Mechanic. "This work forms a valuable sequel to the author's 'Goldsmith's Handbook.'" Silversmiths" Trade Journal. *** The above two works together, strongly half-bound, price 75. Textile Manufacturers' Tables. UNIVERSAL TABLES OF TEXTILE STRUCTURED For the use of Manufacturers in every branch of Textile Trade. By JOSEPH EDMONDSON. Oblong folio, strongly bound in cloth, price 75. 6d. *^~ These Tables provide what has long been wanted, a simple and easy means. of adjusting yarns to "reeds " or " setts," or to "picks " or " shots," and vice versa,, so that fabrics may be made of varying weights or fineness, but having the same character and proportions. CROSBY LOCK WOOD &> CO.'S CATALOGUE. CHEMICAL MANUFACTURES & COMMERCE. T7ie Alkali Trade, Manufacture of Sulphuric Acid, etc. A MANUAL OF THE ALKALI TRADE, including the Manufacture of Sulphuric Acid, Sulphate of Soda, and Bleaching Powder. By JOHN LOMAS, Alkali Manufacturer, Newcastle-upon-Tyne and London. With 232 Illustrations and Working Drawings, and containing 390 pages of Text. Second Edition, with Additions. Super-royal 8vo, i los. cloth. *** This work provides (i) a Complete Handbook for intending Alkali and Sulphuric Acid Manufacturers, and for those already in the field who desire to improve their plant, or to become practically acquainted with the latest processes and developments of the trade : (2) a Handy Volume which Manufacturers can put into the hands of their Managers and Foremen as a useful guide in their daily rounds of duty. "The author has given the fullest, most practical, and, to all concerned in the alkali trade, most valuable mass of information that, to our knowledge, has been published." Engineer. "This book is written by a manufacturer for manufacturers. The working details of the most Approved forms of apparatus are given, and these are accompanied by no less than 232 wood en- gravings, all of which may be used for the purposes of construction. Every step in the manufac- ture is very fully described in this manual, and each improvement explained. Everything which tends to introduce economy into the technical details of this trade receives the fullest attention." Athenamm. " The author is not one of those clever compilers who, on short notice, will ' read up ' any conceiv- able subject, but a practical man in the best sense of the word. We find here not merely a sound and luminous explanation of the chemical principles of the trade, but a notice of numerous matters which have a most important bearing on the successful conduct of alkali works, but which are generally overlooked by even the most experienced technological authors." Chemical Review. Commercial Chemical Analysis. THE COMMERCIAL HANDBOOK OF CHEMICAL ANA- LYSIS; or, Practical Instructions for the determination of the Intrinsic or Commercial Value of Substances used in Manufactures, in Trades, and in the Arts. By A. NORMANDY, Editor of Rose's "Treatise on Chemical Analysis." New Edition, to a great extent Re-written, by HENRY M. NOAD, Ph.D., F.R.S. With numerous Illustrations. Crown 8vo, i2s. 6d. cloth. " We strongly recommend this book to our readers as a guide, alike indispensable to the house- wife as to the pharmaceutical practitioner." Medical Times. "Essential to the analysts appointed under the new Act. The most recent results are given, end the work is well edited and carefully written." Nature. Dye-Wares and Colours. THE MANUAL OF COLOURS AND DYE-WARES : Their Properties, Applications, Valuation, Impurities, and Sophistications. For the use of Dyers, Printers, Drysalters, Brokers, &c. By J. W. SLATER. Second Edition, Revised and greatly Enlarged. Crown 8vo, ys. 6d. cloth. "A complete encyclopjedia of the materia tinctoria. The information given respecting each article is full and precise, and the methods of determining the value of articles such as these, so liable to sophistication, are given with clearness, and are practical as well as valuable." Chemist and Druggist. " There is no other work which covers precisely the same ground. To students preparing ifor examinations in dyeing and printing it will prove exceedingly useful." Chemical News . Figments. THE ARTIST'S MANUAL OF PIGMENTS. Showing their Composition, Conditions of Permanency, Non- Permanency, and Adul- terations ; Effects in Combination with Each Other and with Vehicles ; and the most Reliable Tests of Purity. Together with the Science and Arts Department's Examination Questions on Painting. By H. C. STANDAGE. Small crown 8vo, 25. 6d. cloth. This work is indeed multum-in-parvo, and we can, with good conscience, recommend it to o come in contact with pigments, whether as makers, dealers or users." Chemical Review. This manual cannot fail to be a very valuable aid to all painters who wish their work to re and be of a sound character ; it is complete and comprehensive." Spectator. The author supplies a great deal of very valuable information and memoranda as to the ical qualities and artistic effect of the principal pigments used by painters." Builder. AGRICULTURE, LAND MANAGEMENT, etc. 29, AGRICULTURE, LAND MANAGEMENT, etc. Youatt and Burn's Complete Grazier. THE COMPLETE GRAZIER, and FARMER'S and CATTLE- BREEDER'S ASSISTANT. A Compendium of Husbandry; especially in the departments connected with the Breeding, Rearing, Feeding, and General! Management of Stock ; the Management of the Dairy, &c. With Directions' for the Culture and Management of Grass Land, of Grain and Root Crops, the Arrangement of Farm Offices, the use of Implements and Machines, and on Draining, Irrigation, Warping, &c. ; and the Application and Relative Value of Manures. By WILLIAM YOUATT, Esq., V.S. Twelfth Edition, En- larged, by ROBERT SCOTT BURN, Author of " Outlines of Modern Farming," " Systematic Small Farming," &c. One large 8vo Volume, 860 pp., with 244 Illustrations, i is. half-bound. " The standard and text-book with the farmer and grazier." Farmers' Magazine. "A treatise which will remain a standard work on the subject as long as British agriculture endures." Afar* Lane Express (First Notice). The book deals with all departments of agriculture, and contains an immense amount oi valuable information. It is, in fact, an encyclopaedia of agriculture put into readable form, and is is the only work equally comprehensive brought down to present date. It .deserves a place in the library of every agriculturist." Mark Lane Express (Second Notice) "This esteemed work is well worthy of a place in the libraries of agriculturists." North British Agriculturist. Modern Farming. OUTLINES OF MODERN FARMING. By R. SCOTT BURN. Soils, Manures, and Crops Farming and Farming Economy Cattle, Sheept and Horses Management of the Dairy, Pigs and Poultry Utilisation of Town-Sewage, Irrigation, &c. Sixth Edition. In One Vol., 1,250 pp., half- bound, profusely Illustrated, i2S. " The aim of the author has been to make his work at once comprehensive and trustworthy, and in this aim he has succeeded to a degree which entitles him to much credit." Morning- Advertiser. "Eminently calculated to enlighten the agricultural community on the varied subjects of which it treats, and hence it should had a place in every farmer's library." City Press. Small Farming. SYSTEMATIC SMALL FARMING; or, The Lessons of my Farm. Being an Introduction to Modern Farm Practice for Small Farmers- in the Culture of Crops ; The Feeding of Cattle ; The Management of the Dairy, Poultry and Pigs ; The Keeping of Farm Work Records ; The Ensilage- System, Construction of Silos, and other Farm Buildings ; The Improve- ment of Neglected Farms, &c. By ROBERT SCOTT BURN, Author of " Out- lines of Landed Estates' Management," and " Outlines of Farm Manage- ment," and Editor of " The Complete Grazier." With numerous Illustrations, crown 8vo, 6s. cloth. [fust published. "This is the completes! book of its class we have seen, and one which every amateur farmer will read with pleasure and accept as a guide." Field. "Mr. Scott Burn's pages are severely practical, and the tone of the practical man is fe\ CO.' S CATALOGUE. A Complete Epitome of the Laws of this Country. EVERY MAN'S OWN LAWYER: A Handy-book of the Principles of Law and Equity. By A BARRISTER. Twenty-third Edition, Carefully Revised and brought down to the end of the last Session, including Summaries of the Latest Statute Laws. With Notes and References to the Authorities. Crown 8vo, price 6s. &d. (saved at every consultation), strongly bound in cloth. Comprising THE RIGHTS AND WRONGS OF INDIVIDUALS MERCANTILE AND COM- MERCIAL LAW CRIMINAL LAW PARISH LAW COUNTY COURT LAW GAME AND FISHERY LAWS POOR MEN'S LAWSUITS THE LAWS OF BANKRUPTCY BETS AND WAGERS CHEQUES, BILLS, AND NOTES CONTRACTS AND AGREEMENTS COPYRIGHT ELECTIONS AND REGISTRATION INSURANCE LIBEL AND SLANDER MARRIAGE AND DIVORCE MERCHANT SHIPPING MORTGAGES SETTLEMENTS STOCK EXCHANGE PRACTICE TRADE MARKS AND PATENTS TRESPASS NUISANCES, &c. TRANSFER OF LAND, &c. WARRANTY WILLS AND AGREEMENTS, &c. &c. Opinions of the Press. "No Englishman ought to be -withoiit this book. . . . Any person perfectly uninformed on legal matters, who may require sound information on unknown law points, will, by reference to this book, acquire the necessary information, and thus on many occasions save the expense and loss of time of a visit to a lawyer." Engineer. " It is a complete code of English Law, written in plain language, which all can understand." Weekly Times. "A useful and concise epitome of the law, compiled with considerable care." Laiu Magazine. "What it professes to be a complete epitome of the laws of this country, thoroughly intelli- gible to non-professional readers. The book is a handy one to have in readiness when some knotty point requires ready solution." Belts Life. Metropolitan Hating Appeals. REPORTS OF APPEALS HEARD BEFORE THE COURT OF GENERAL ASSESSMENT SESSIONS, from the Year 1871 to 1885. By EDWARD RYDE and ARTHUR LYON RYDE. Fourth Edition, brought down to the Present Date, with an Introduction to the Valuation (Metropolis) Act, 1869, and an Appendix by WALTER C. RYDE, of the Inner Temple, Barrister- at-Law. 8vo, i6s. cloth. House Property. HANDBOOK OF HOUSE PROPERTY : A Popular and, Practical Guide to the Purchase, Mortgage, Tenancy, and Compulsory Sale of Houses and Land. By E. L. TARBUCK, Architect and Surveyor. Third Edition, 12100,. 35. 6d. cloth. " The advice is thoroughly practical." Laiu Journal. "This is a well-written and thoughtful work. We commend the work to the careful study of ali interested in questions affecting houses and land." Land Agents' Record. Inwood's Estate Tables. TABLES FOR THE PURCHASING OF ESTATES, Freehold, Copyhold, or Leasehold; Annuities, Advowsons, &c. t and for the Renewing o* Leases held under Cathedral Churches, Colleges, or other Corporate bodies* for Terms of Years certain, and for Lives ; also for Valuing Reversionary Estates, Deferred Annuities, Next Presentations, &c. : together with SMART'S Five Tables of Compound Interest, and an Extension of the same to Lower and Intermediate Rates. By W. INWOOD. 22nd Edition, with considerable Additions, and new and valuable Tables of Logarithms for the more Difficult Computations of the Interest of Money, Discount, Annuities, &c. , by M. FEDOR THOMAN, of the Societe Credit Mobilier of Paris. 12010, 8s. cloth. "Those interested in tne purchase and sale of estates, and in the adjustment of compensation. cases, as well as in transactions in annuities, life insurances, &c., will find the present edition of eminent service. " Engineering. " ' Inwood's Tables ' still maintain a most enviable reputation. The new issue has been enriched by large additional contributions by M. Fedor Thoman, whose carefully arranged Tables cannot fail to be of the utmost utility." Mining Journal. Agricultural and Tenant-Right Valuation. THE AGRICULTURAL AND TENANT-RIGHT-VALUER'S ASSISTANT. By TOM BRIGHT, Agricultural Surveyor, Author of "The Live Stock of North Devon," &c. Crown 8vo, 3$. 6d. cloth. [Just published. Full of tables and examples in connection with the valuation of tenant-right, estates, labour, contents, and weights of timber, and farm produce of all kinds. The book is well calculated to assist the valuer in the discharge of his duty." Agricultural Gazette. J. OGDEN AND CO., PRINTERS, 29, 30 AND 31, GT. SAFFRON HILL, E,C. a&trtrfmentarj) LONDON, 1862, THE PRIZE MEDAL Was awarded to the Publishers of "WEALE'S SERIES." A NEW LIST OF WEALE'S SERIES RUDIMENTARY SCIENTIFIC, EDUCATIONAL, AND CLASSICAL. Comprising nearly Three Hundred and Fifty distinct works in almost every department of Science, Art, and Education, recommended to the notice of Engineers, Architetts, Builders, Artisans, and Students generally, as -well as to those interested in Workmen's Libraries, Literary and Scientific Institutions, Colleges, Schools, Science Classes, &*c., &-c. IS" " WEALE'S SERIES includes Text-Books on almost every branch of Science and Industry, comprising such subjects as Agriculture, Architecture and Building, Civil Engineering, Fine Arts, Mechanics and Mechanical Engineering, Physical and Chemical Science, and many miscellaneous Treatises. The whole are constantly undergoing revision, and new editions, brought up to the latest discoveries in scientific research, are constantly issued. The prices at which they are sold are as low as their excellence is assured." American Literary Gazette. " Amongst the literature of technical education, WEALE'S SERIES has ever enjoyed a high reputation, and the additions being made by Messrs. CROSBY LOCKWOOD & SON render the series even more complete, and bring the infor- mation upon the several subjects down to the present time." Mining Journal. " It is not too much to say that no books have ever proved more populai with, or more useful to, young engineers and others than the excellent treatises comprised in WEALE'S SERIES." Engineer. "The excellence of WEALE'S SERIES is now so well appreciated, that it would be wasting our space to enlarge upon their general usefulness and value .' ' Builder. " WEALE'S SERIES has become a standard as well as an unrivalled collection of treatises in all branches of art and science." Public Opinion. PHILADELPHIA, 1876. THE PRIZE MEDAL Was awarded to the Publishers for Eooks : Rudimentary, Scientific, "WEALE'S SERIES," ETC. CROSBY LOCKWOOD & SON, STATIONERS' HALL COURT. LUDGATK HILL. LONDON. E.G. WEALE'S RUDIMENTARY SERIES. WEALE'S RUDIMENTARY SCIENTIFIC SERIES. V* The volumes of this Series are freely Illustrated with Woodcuts, or otherwise, where requisite. Throughout the fol- lowing List it must be understood that the books are bound in /"^ TO Y limp cloth, unless otherwise stated ; but the volumes marked |atHO TO |mnei Wl - th a j may a i so oe had strongly bound in cloth boards for 6d. extra. N.B. In ordering from this List it is recommended, as a means of facilitating business and obviating error, to quote the numbers affixed to the volumes, as well as the titles and prices. CIVIL ENGINEERING, SURVEYING, ETC. No. 31. WELLS AND WELL-SINKING. By JOHN GEO. SWINDELL, A.R.I.B.A., and G. R. BURNELL, C.E. Revised Edition. With a New Appendix on the Qualities of Water. Illustrated. 2S. 35. THE BLASTING AND QUARRYING OF STONE, for Building and other Purposes. With Remarks on the Blowing up of Bridges. By Gen. Sir JOHN BURGOYNE, Bart., K.C.B. Illustrated, is. 6d. 43. TUBULAR, AND OTHER IRON GIRDER BRIDGES,?- ticularly describing the Britannia and Conway Tubular Bridges. By G. DRYSDALE DEMPSEY, C.E. Fourth Edition. 2s. 44. FOUNDATIONS AND CONCRETE WORKS, with Practical Remarks on Footings, Sand, Concrete, Beton, Pile-driving, Caissons, and Cofferdams. &c. By E. DOBSON. Fifth Edition, is. 6d. 60. LAND AND ENGINEERING SURVEYING. By T. BAKER, C.E. New Edition, revised by EDWARD NUGENT, C.E. as.t 80*. EMBANKING LANDS FROM THE SEA. With examples and Particulars of actual Embankments, 8cc. By T. WIGGINS, F.G.S. 2s. 8 1. WATER WORKS, for the Supply of Cities and Towns. With logical fluencing Supplies of Water ; and Details of Engines and Pumping Machinery a Description of the Principal Geological Formations of England as in- fluencing Supplies of Water ; and Details of Engines and Pumping Machiner for raising Water. By SAMUEL HUGHES, F.G.S., C.E. New Edition. 45.* 1 1 8. CIVIL ENGINEERING IN NORTH AMERICA, a Sketch of. By DAVID STEVENSON, F.R.S.E., &c. Plates and Diagrams. 35. 167. IRON BRIDGES, GIRDERS, ROOFS, AND OTHER WORKS. By FRANCIS CAMPIN, C.E. 2s. 6d.J 197. ROADS AND STREETS (THE CONSTRUCTION OF). By HENRY LAW, C.E., revised and enlarged by D. K. CLARK, C.E., including pavements of Stone, Wood, Asphalte, &c. 45. 6d.i 203. SANITARY WORK IN THE SMALLER TOWNS AND IN VILLAGES. By C. SLAGG, A.M.I.C.E. Revised Edition. 3 s.t 212. GAS-WORKS, THEIR CONSTRUCTION AND ARRANGE- MENT', and the Manufacture and Distribution of Coal Gas. Originally written by SAMUEL HUGHES, C.E. Re-written and enlarged by WILLIAM RICHARDS, C.E. Seventh Edition, with important additions. 55. 6d.J 213. PIONEER ENGINEERING. A. Treatise on the Engineering Operations connected with the Settlement of Waste Lands in New Coun- tries. By EDWARD DOBSON, Assoc. Inst. C.E. 45. 6d.t 2 1 6. MATERIALS AND CONSTRUCTION; A Theoretical and Practical Treatise on the Strains, Designing, and Erection of Works of Con- struction. By FRANCIS CAMPIN, C.E. Second Edition, revised. 354 219. CIVIL ENGINEERING. By HENRY LAW, M.Inst. C.E. Including HYDRAULIC ENGINEERING by GEO. R. BURNELL, M.Inst. C.E. Seventh Edition, revised, with large additions by D. KINNBAR CLARK, M.Tnst. C.E. 6s. 6d.. Cloth boards, 7 s. 6d. The i indicates that these vois. may be had strongly bound at 6d. extra. LONDON I CROSBY LOCKWOOD AND SON, WEALE'S RUDIMENTARY SERIES. MECHANICAL ENGINEERING, ETC. 33. CRANES, the Construction of, and other Machinery for Raising Heavy Bodies. By JOSEPH GLYNN, F.R.S. Illustrated, is. 6d. 34. THE STEAM ENGINE. By Dr. LARDNER. Illustrated, is. 6d. 59. STEAM BOILERS : their Construction and Management. By R. ARMSTRONG, C.E. Illustrated, is. 6d. 82. THE POWER OF WATER, as applied to drive Flour Mills, and to give motion to Turbines, &c. By JOSEPH GLYNN, F.R.S. 2s.t 98. PRACTICAL MECHANISM, the Elements of; and Machine Tools. By T. BAKER, C.E. With Additions by J. NASMYTH, C.E. as. 6d.* 139. 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