lxi 
- boilers, engines, and pit-work,* the lower tension of the steam 
used, and the (consequently) diminished amount of expansive 
working,t—the inferiority of the coal now used when compared 
with that in use formerly,{—and the change of interests—from 
resident proprietors, studious of economy, and seeking profit from - 
legitimate mining only, to speculative strangers taking advantage 
of fluctuations in the share-markets and indifferent to everything 
* “The performance of Cornish engines, compared with what it was 
““some few years ago, has fallen off from 20 to 25 per cent. This was, no 
“ doubt, partly attributable to the machinery getting older and from corro- 
* sion of the pumps.” Lean, West Briton, lxii., (No. 3,185), p. 3. 
+ ‘‘As the load increases by the increased depth of the mine, the 
*“ machinery becomes weaker by age and wear, and hence, when economy is 
“most wanted, it is least attainable.” Ponr, Cornish Pumping Engine, p. 
134. 
‘ Formerly the practice of working expansively was carried to a greater 
‘extent than it is now.” Morsueap, Proceedings of the Inst. of Ciwil Engi- 
neers, XXiil., p. 48. 
«“‘The Cornish Engine had afforded numerous examples of the success- 
“ful use of high-pressure steam and large expansion, perhaps half a century 
“ before the same advantages were secured for rotary engines.” Putpps, /bid, 
p. 74. 
“The principal advantage lay in the Cornish, or Trevithick’s, boiler and 
“the use of high pressure steam.... Practically expansion had not been 
“ ¢arried out in Watt’s engines in Cornwall, even by Watt himself.” Hus- 
BAND, Jbid, pp. 76, 81. Ante, p. 45. Note || 
+ “The variation in the quality of coal, even from the same pit, is 
“‘oreat; and the economy of attending to this will be found to vary from 
“ one-twelfth to one-fifth of the consumption.” Browne, Cornish Engine 
Reporter, No. 8. 
The weight of water evaporated from a temperature of 212° by 1 Ib. of 
Welsh Coal (mean of 37 samples) was found to be.... 9°05 lbs. 
Neweastle ,, ( = 17 Spit) % Nase Orone ies 
Lancashire ,, ( " PAS) a Mens seed on 5 Socio UTES aap 
Scotch eg (ecie iss Syeeearesnan <i) a Hares Oley, 
Derbyshire ,, ( Be 8 oo han) 3 sole MO Ol ay 
Puruurps and Dariineron, Records of Mining and Metallurgy, p. 65. 
“Tt is well-known that the evaporative power of the different coals em- 
“ployed in Cornwall, varies considerably, and that the coal now in use is 
‘‘inferior to what it was twenty years ago.” Morsurap, Proceedings of the 
Inst. of Civil Engineers, xxiii., p. 47. 
‘Mines were now managed by committees of adventurers, each pro- 
“‘bably trading with the mine in some department ;.... and it was of little 
“‘use, under such circumstances, for the Engineer to find fault with the 
“¢ coals he had to burn.”—Greaves, /bid, p. 68. 
‘A large part of the falling off [in duty] was due to the inferior quality 
‘< of the coal too often supplied to the mines.... [There is] every reason to 
‘‘ believe that the county.... actually lost to the extent of £25,000 to 
‘¢ £30,000 a year owing to the rubbish supplied in the way of coal.” Lan, 
‘West Briton, \xii., (No. 3,185) p. 3. 
