Intelligence and. Miscellaneous Articles. 



31. 



copper ore, which on an average has yielded about 9^ per cent, of copper 

 and36| tons of tin ore. The ores have been sold for £548,872, of which 

 one twenty-fourth has been paid to the lord of the soil as rent. T lie- 

 total cost of working the mines has been £462,444 ; leaving a clear 

 profit of £63,604. 



The above is but a limited view of the advantages arising from the 

 use of Mr. Woolf's engines ; for if the mines had been begun in 1819 

 with Mr. Watt's engines, the loss during the first years would have 

 been considerably greater than it was, and the mines would have 

 continued to be unprofitable for a longer time than three years ; also 

 the subsequent profit would have been so much smaller than it has 

 been, that it would not have repaid the previous loss (and interest 

 upon the capital advanced) for a long time to come, beyond the present 

 date, supposing the mines to continue to yield ore. In fact if these 

 mines could have been worked with profit by Mr. Watt's engines, 

 they would not have been given up as they were, twenty-five years 

 ago, when they were not worked out so deep, or so extensively, as 

 they are now. 



Engines and Cost of Drainage at the Consolidated and United Mines. 



Date. 



No. of 

 Engines. 



Horse 

 Power. 



Average 

 Millions. 



Cost of 

 Drainage. 



Clear 

 Profit. 



Expense 

 saved. 



1825 

 1826 



1827 

 1828 

 1829 



4 

 6 



8 

 8 

 8 



432 



422 

 378 

 526 

 513 



31-04 

 32-31 

 36-76 



44-86 

 51-81 



£17776 

 13543. 

 13426 

 12428 

 11958 



£4169 

 7648 

 13294 

 22314 

 16179 



£9824 

 8337 

 11254 

 15452 

 19042 



Aver s . 



7 



454 



39-36 



£13826 



£12721 



£12782 



The last column of the table shows the saving that has been made 

 by the use of Mr. Woolf's engines, or the increase in the cost of 

 drainage that would have been incurred by using Mr. Watt's engines, 

 raising twenty millions, instead of the engines actually used : those 

 savings are included in and form part of the profits ; and without them 

 the extra expense would have absorbed more than all the profit in 

 1825, 1826 and in 1829 ; so that instead of profit, the adventurers 

 would have lost £5655 in 1825, £689 in 1826,and £2863 in 1829. 

 Or taking the whole of the last five years, no profit would have been 

 made ; and it would have been more advantageous to the adventurers 

 to have broken up their establishment, and sold the materials, than 

 to have continued working. 



In conclusion, it may be safely asserted that the saving in fuel re- 

 sulting from the general use of Mr. Woolf's system of working steam- 

 engines by high-pressure steam acting expansively (instead of Mr. 

 Watt's system of working them by low-pressure steam acting expan- 

 sively), constitutes the present profits of deep mining in Cornwall. 



37, Howland Street, Fitzroy Square, John Farey. 



London, June 5, 1830. 



2 S 2 CIRCU- 



