<*> A major published source of data on engines and mines is D.B.Barton's 'The Cornish Beam Engine', published in 1966. Barton has grouped the material in a general chronological history plus a number of themes (the engine itself, pitwork, boilers, houses, foundries, etc.). For engine and site tables this vast amount of detailed info - gleaned from e.g. countless volumes of regional newspapers - has been used to supplement the data from Lean and Burt (see below). For all other aspects Barton's data, extracted and re-ordered - and in some cases corrected - have played a major role.
<*> For data on engines in Cornwall, the backbone of the source material is Lean's Engine Reporter which appeared from 1811 to c.1904. This is not compre- hensive: each monthly issue reported on at most fifty or sixty engines, while the maximum number of engines simultaneously present in the Duchy is estimated at possibly over 600. Initial data entry was based on photocopies of selected issues, and so a few engines with short reporting periods may have been missed. Lean provides 'snapshots', and does not contain much by way of engine context, such as where and when an engine was made, where it came from, or where it went later. For the engines in the UK outside Cornwall, Brian Hillsdon has supplied extensive new, supplementary and corrective data.
<*> For sites in Cornwall the major source for mineral mining sites in the period 1845-1913 is:
R.Burt, P.Waite, R.Burnley 'Cornish Mines',1987
supplemented by data culled from many sources. The 1845 cutoff sometimes (falsely but inevitably) suggests startup in that year.
<*> Most data on engineers have been abstracted from Barton and from: T.R.Harris 'Some Lesser Known Cornish Engineers', JTS#5p27.
<*> Data on foundries are primarily from Barton, supplemented from many sources. The extensive index by J.Ferguson in JTS#25 has been used to verify details; as that survey does not list products, it could not be used to supplement the list of engine manufacturers.
<*> General sources of supplementary and corrective data include:
M.Bone, P.Stanier 'A Guide to the Industrial Archaeology of Devon', 1998.
KMB's comprehensive compilation of sales notices in the Cornish press, ranging from 1802 to 1895. A copy of this unpublished manuscript has been deposited with the Cornwall Archeological Unit in Truro.
KMB's 'Enginehouse Site List', part 'Rest of Kerrier', compiled 1997 for CAU.
W.Browne's 'Cornish Engine Reporter', published from Mar 1847 to 1858, available issues #12(Jan 1848), #19(Aug 1848), #95(Dec 1854), plus notes in the Mining Journal based on issues Nov 1851 and Aug 1855, plus notes by KMB. KMB has access to issues 1-8 and 13-18 inclusive (microfilm now at Redruth Library).
W.J.Henwood 'Statistics of the Mines in Cornwall and Devon' in Trans.RGSC 1843, reflecting the 1838 situation, but data from other sources show this survey to be far from comprehensive.
B.Howard 'Was the Bushel 84 lbs or 94 lbs?' JTS#29p123ff.
T.Lean 'Historical Statement on the Steam Engines in Cornwall', 1839.
Trevithick Society Journals (JTS).
O.Wagenbreth, H.Dntzsch, A.Gieseler 'Die Geschichte der Dampfmaschine', 2002.
G.Watkins 'The Steam Engine in Industry' Vol.1, 1978.
<*> Special sources for e.g. a particular mine, or region, or manufacturer, or engineer, include:
J.Lewis 'A Richly Yielding Piece of Ground - The Story of Fowey Consols Mine near St.Blazey', 1997.
W.H.Pascoe 'C.C.C.- The History of the Cornish Copper Company', 1981.
<*> The following possible source material has been noted, but not yet fully scanned for relevant data.
D.B.Barton 'Essays in Cornish Mining History', Vol.1 1968, Vol.2 1970.
D.B.Barton 'Copper Mining in Cornwall and Devon', 3rd ed.1978.
K.M.Brown, R.S.Acton 'Exploring Cornish Mines' Vol.1 1994, Vol.2 1995, Vol.3 1997, Vol.4 1999.
J.A.Buckley 'A History of South Crofty Mine',ed.1997.
R.Burt 'Cornish Company Records' JTS#19p32/43.
J.H.Collins 'Observations on the W. of England Mining Region', 1912.
J.Corin 'Levant - A Champion Cornish Mine',2nd ed.1997.
H.L.Douch 'East Wheal Rose',1964.
G.J.Drew & J.E.Donnell 'Cornish Beam Engines in S. Australian Mines',1993.
A.K.Hamilton Jenkin 'Mines and Miners of Cornwall',1961-1970.
T.R.Harris 'Arthur Woolf- The Cornish Engineer',1966.
T.R.Harris 'Dolcoath - Queen of Cornish Mines',1974.
P.Heffer 'East Pool & Agar - A Cornish Mining Legend',1985.
B.Hollowood 'Cornish Engineers',1951 (Holman company history).
F.Bice Michell 'Michell - A Family of Cornish Engineers',1984.
C.Noall 'Botallack',ed.1999 C.Noall 'Geevor Tin Mines',1983.
F.M.G.von Pambour 'Theorie der Dampfmaschinen',1849 (after 1844 French ed.).
W.Pole 'Treatise on the Cornish Engine',1844.
T.Spargo 'The Mines of Cornwall; Statistics & Observations',1865.
J.H.Trounson 'Mining in Cornwall', Vol.1 & 2 1980.
E.Vale 'The Harveys of Hayle', 1966.
Trevithick Society Newsletters
<*> If it should be decided to extend the database to earlier (non-Cornish) pumping engines, the following should be of interest.
H.W.Dickinson, Rhys Jenkins 'James Watt and the Steam Engine', 1927.
T.R.Harris 'The Hornblower Family',1976, JTS#4p7/44.
L.T.C.Rolt, J.S.Allen 'The Steam Engine of Thomas Newcomen', 3rd ed.1997 (has a list of early Newcomen engines, plus a comprehensive bibliography; J.S.Allen and J.Andrew might be consulted).
H.Torrens 'New light on the Hornblower & Winwood Compound Steam Engine', JTS#9p21/42.
<*> Note on source references: While sources for data are given in many cases, this has not been done dogmatically. In particular, if an engine has figured in Lean for an extended period, we have refrained from referencing every instance. It has also become evident during the gathering of data, that several authors have borrowed material from predecessors without precise source referencing, which makes accurate pinpointing of the original source, or judgment of the reliability of sources, somewhat difficult. If no explicit source reference given, the data usually originate from KMB's files. Individual - even subjective - judgment inevitably plays a part.
|AKHJ||Hamilton Jenkin's 'Mines and Miners of Cornwall'.|
|B&WRef||Boulton & Watt reference Collection, Birmingham.|
|BEH||Brian E. Hillsdon's research files.|
|Burt||Burt's 'Mines in Cornwall'.|
|DBBnn||Barton's 'Cornish Beam Engine' page nn.|
|D&RJnn||Dickinson & Rhys Jenkins 'J.Watt & the Steam Engine' page nn.|
|JBR||Justin Brooke's Records.|
|LERyyyy/mm||Lean's Engine Reporter for month mm in year yyyy.|
|BERyyyy/mm||Browne's Engine Reporter for month mm in year yyyy.|
|SERnnn(yyyy)||Photo nr.nnn, taken in yyyy, in George Watkins' Steam Engine Record at English Heritage, Swindon.|
|FTR||(in connection with Lean/Browne) First time reported.|
|NFTR||(ditto) This is not the first report for this engine.|
|LTR||(ditto) Last time reported.|
|LHSnn||Lean's 'Historical Statement ...' page nn.|
|LHS(yyyy)||Lean's 'Historical Statement ...' table for the year yyyy (for readability, the year has been used rather than the table number).|
|ECM#vvpnn||Brown/Acton's 'Exploring Cornish Mines' Vol.vv page nn.|
|JTS#vvpnn||Journal of the Trevithick Society, Vol.vv page nn.|
|NTS#kkkpnn||Newsletter of the Trevithick Society, issue kkk page nn.|
|(R)CGyyyy/mm/dd||(Royal) Cornwall Gazette with date (if known; 'Royal' from 1810).|
|WByyyy/mm/dd||West Briton with date (if known).|
|MJyyyy/mm/dd||Mining Journal with date (if known).|
|JGasL||Journal of Gas Lighting.|
|RoKnnnn||Enginehouse site list 'Rest of Kerrier', nr.nnnn.|
In several cases, references are given as the author's name-plus-page (no spaces), e.g. Pascoe110. Where this might confuse, the full reference is given.
|Bal||Cornish for 'mine', and thus part of some mine names (but far less common than the more general 'wheal', q.v.)|
|Bushel||A quantity measure for coal - originally a capacity measure with an assumed weight equivalent, formally superseded by imperial weight units in 1834. Used to define and measure engine duty, and more fully discussed under that heading.|
|Compound||Steam expansion in two stages, in two cylinders, or at any rate in two spaces. Hornblower built the first compound or 'combined' engines in the late 18th century, for developments in Cornwall the principal types were the Woolf compound (two cylinders side by side, often 2:1 diameter ratio), the pole compound (plunger or pole HP, based on Trevithick's 1816 pole engine but most were built by William Sims), and Sims compound (two cylinders in tandem, mostly built by James Sims).|
|Depth||The total lift of the pumps on an engine. This is not always the depth of the mine, but usually the depth from adit level. In some cases (shammalling, q.v., non-mine working such as water supply, canal supply, sewage pumping, land drainage) the lift may be differently defined. Where the depth has been arrived at by adding lifts of individual pumps (as given e.g. in LER), the uncertainty is expressed by (?) after the figure in the 'raw notes' discussed earlier.|
|Duty||is a figure for comparing the overall efficiency of coal-fired steam engine installations. It quantifies the useful work achieved by the combustion of a standard quantity of coal, usually in the form 'pounds of water raised one foot by burning a bushel of coal'. As the figures run into many millions, it is customary to abbreviate them, e.g. 48m for 48 million ft.lbs per bushel. The quality of the coal was, of course, important and it was often specified, e.g. 'best Welsh steam coal'. The definition hides a few simplifications, such as neglecting the pump losses, and the concept is mainly suitable for comparing similar engines, or to chart the progress (or otherwise) of a particular engine. It is not an absolute efficiency measure, although it was (and is) sometimes misinterpreted as such. It may vary widely: Trestrail notes that the monthly average duty of E-0528 over 1895 varied from 24 to 51 million. In important disputes a formal 'duty trial' was resorted to, where independent experts recorded the conditions and supervised the proceedings. The duration of such a trial was important: the longer, the more reliable (and usually lower) the duty figures were. 24-hour trials were common, but even then e.g. careful boiler management before the trial could significantly influence the results. See what Barton has to say about the famous Austen's 80" engine (E-0228) trial in Oct 1835 (DBB49-51).
Many sources use the unit "bushel" without defining it - its size was apparently assumed to be common knowledge. The bushel, being a capacity measure, was first used in the definition of duty in the 18th century (Watt, Smeaton), and was then understood to be conventionally equivalent to 84 lbs coal. B.Howard (JTS#29p123-128) has studied what happened in Cornwall later. Lean noted in 1831, that the actual weight of a bushel could vary widely (80-100 lbs). When, in 1834, the 84 lb bushel was legally abolished, Lean did not immediately switch to the Imperial weight measure (i.e. the 112 lb cwt), but he maintained apparent continuity by introducing a 94 lb bushel of his own invention, and by actively promoting the idea that this had been the unit all along. Quotations from pre-1834 sources were often doctored to convey the 94 lb suggestion. The value 94 lb would, at any rate, probably be fairly close to the average actual weight of the old bushel. One would, of course, not expect a capacity-measured "Lean" bushel to weigh exactly 94 lbs, though that is precisely what the Austen's trial report asserts! From Oct 1838 Lean formally adds "94 lb" to the bushel column. From 1847 he reports both bushel- and cwt-based duties, and in 1856 the bushel is dropped from the Engine Reporter.
Should the database pre-1834 entries be corrected? In view of the actual weight of the "84 lb" bushel reported above, and of the rather crude nature of the duty as a measure of efficiency, this was not deemed necessary. The database thus cites only values per 94 lb bushel and only converts cwt-based duties. Later, one also encounters coal consumption per hp.h, and in modern literature efficiency figures are usually given as a fraction or %. Roughly (for an average Welsh steam coal) a duty of 10 million ft.lb per 94 lb bushel corresponds to an overall efficiency of 1 %.
|Lift||Often the total height over which the water is raised; but also used for one pump with its cistern plus rising main to the next pump above it in the shaft. The lifts in a shaft have traditional names. The 'tye lift' raises the water to its final discharge level, often an adit, sometimes the top of the shaft. It usually has the largest diameter (plunger) pump. Above it may be the (usually much smaller) 'house lift', supplying process water to equipment at surface. Down- wards from the tye lift come the 'rose lift' and the 'puppy lift'. The bottom lift is a bucket lift drawing from the 'sump' at the bottom of the shaft. As the shaft is sunk further, the bottom lift is extended, until another plunger lift can be inserted above it. The usual height of a plunger lift is c.25-30 fm, or c.50-60 m.|
|Pitwork||'All parts below the nose of the bob', i.e. the rods, pumps, piping and ancillary structures down the shaft, including flat rods, angle bobs, etc. at surface. At present the database has entries for the diameter of the largest pump and for the lift. These cannot represent the full variety of pitwork. In many cases it is difficult to abstract meaningful pump and lift figures from the more elaborate - but often incomplete - data in Lean or Browne. Elsewhere, pitwork data are scarce. As a result these data, while giving an impression, are of questionable value for characterizing an engine or a working.|
|Pump size||The diameter of the pump in the topmost lift, usually the lift to the adit (tye lift), in most cases the largest pump. At an earlier stage, this was entered as e.g. '16" down' (meaning '16", tapering off downward in the shaft', or (erroneously) 'down 16"', and in the database entries this style may still be encountered.|
|The practice of having two engines, each pumping part of the depth of a shaft, e.g. one engine from sump to 60 fm below adit, and the second or shammal engine the remaining 60 fm to adit. An example is the 63" Great Engine at Dolcoath (E-0027) and its 45" Shammal Engine (E-0028). It is not always clear, however, which of the two engines in a shammal setup is called the 'shammal engine'. In most cases LHS indicates that the engine with the lower set of lifts 'shammals to' the higher set, which would seem to be at variance with the above designation of E-0028.
As engines became more powerful, the practice of shammalling gradually died out, but as late as 1886 the pumping arrangement at the Severn Tunnel Sudbrook station #1 is in fact a shammal setup.
|Speed||is usually the average (in strokes per minute) over a period of time which may include idle periods. It is thus not indicative of the momentary speed, or speed capacity, of an engine.|
|Steaming||lists data on the steam supply (boilers). In the source material they are given in several forms. When Lean started including boiler data in 1846, these included the number, the principal dimensions (diameter and length), and the boiler weight. Soon, pressure was added. In 1860 Lean dropped the dimensions of individual boilers. In the database this latter convention is followed: number, total weight, pressure. Roughly, a 10t boiler would be 6'x31', and a 12t one would be 6'6"x35'.|
|Wheal||(older form Huel) Cornish for 'work', and part of many mine names. See also 'bal'.|
|Working||is generally used to denote a period of activity at a mine. Within the context of this database it is mostly used (slightly more restrictively) for the period of activity of an engine at a site.|