Undercover - Steam Power - Book 5

Part 7 - Ting-Tang mine

While we ate supper, Mr Watt told us he intended to visit the Ting Tang mine near Carharrack about 2 km from Redruth. 'One of ma engines was installed nearly a year ago. But it still diznna wurrk for some obscure reason. The mine owner replaced an old common engine with one of ours. Although ours has only a 52 inch diameter (1.32 m) cylinder, it is more powerful as it will obtain a vacuum of ten pounds per square inch (psi) because of my separate steam condenser. Whereas the common engine, with a 63 inch diameter cylinder, cannot make a vacuum greater than seven pounds per square inch.'

I quickly estimated the force lifting water out of the mine. 'Pi times diameter squared divided by 4, times the pressure. (For a rough estimate that's three quarters of a 52 inch square x 10 psi). That's incredible,' I said. 'The piston is lifting over twenty thousand pounds of water.'

Mr Watts looked surprised. 'That's aboot right, laddie. You have been well educated.'

'We have very good schools in Canada,' Denny said.

'There is much work to do, Mr Vernier,'  Mr Watt said, 'and I should be pleased to have some trustworthy help for I not only ha' to superintend the erection of the engines but I ha' to make drawings for new engines and correspond with a dozen makers of small parts. Nothing seems to go right. There are defects in castings, materials and workmanship and delays in delivery and the workmen are invariably drunk, or incapable, or both. 

 And, if ye can think of a satisfactory way of packing these pistons, to stop steam leaking, I should be in your debt forever. The best I ha' come up wi' is oakum and rope which must be quite free from any tar for, if it requires to be greased, the enginemen will eat the grease for their dinner.'

We were so tired from our days of sleeping in hammocks and barn lofts, and our beds were so soft and comfortable, that I felt as if I were floating on a cloud as I fell asleep that night. It was not easy getting up when we were awakened early for a breakfast of eggs, bacon and toast. After navy food, this was paradise and we ate everything we could get, just in case this was the last food we would see for awhile. 

 We had just finished when an open carriage stopped outside the house. It was driven by a well dressed man and contained two ladies. He introduced himself. 'Jonathan Hornblower, Esquire, copper and tin mine adventurer, at your service, gentlemen.' 

 Mr Watt introduced us in turn to Mr Hornblower's wife and his daughter, Megan, who was about Licia's age. 'That's a bonnie lassie ye have, Mrs Hornblower,' Mr Watt said as Mrs Tutchin and the maid quickly swept away the remains of our breakfast and produced another pot of tea for the guests. 

 By this time Mr Hornblower and Mr Watt were discussing the problems with the pumping engine at his mine. 'The old common engine had been pumping water out of the Tin Tang mine for the past forty years,' Mr Hornblower said. 'But it was costing me a fortune in coal and repairs. I could only afford to keep it pumping because the tin mines are exempt the duty on coal. John Budge, kept the old common engine working for many years and it was he who replaced it with your engine last year. But, he has not been able to get it working properly and the mine is again flooded.'

'Old Bouge - for that is how John Budge is called - claims your engine uses as much coal as the old common engine did but it is more complicated so it breaks down more often. Now, I can't argue with Old Bouge for he is the most experience mill and engine wright in Cornwall but perhaps he doesn't understand the nature of your invention and that is why, in desperation, I asked you to come down from Birmingham.'

Denny, Alfie, Miguel and I were interested in the discussion but Megan was sitting in the corner while Licia admired her elegant long dress and eventually they disappeared.

Mr Watt had listened to the tale with growing impatience. 'Dinna fash yersel', Mr Hornblower,' he burst out. 'Ye shall have your fire engine working and it'll not waste a particle of steam.'

 'I must tell you,' Mr Hornblower continued, 'Old Bouge has advised me to scrap your engine and buy an engine from John Smeaton.'

'I have tested Mr Smeaton's improved common engine,' Mr Watt spoke tersely as he strove to remain polite. 'I found it will raise nine million pounds of water, one foot high for each bushel of coal burned, and this is indeed better than the average common engine which I have found will fork seven million at best. However, I ha' tested ma engine and found it has a duty of twenty five million or more.'

' So ye can see ma engine will burn almost one quarter the amount of coal for the same amount of water pumped compared to your old common engine. Mr Smeaton's engine for the new dry dock at Kronstadt in Russia needs three boilers ten foot in diameter just to supply the steam for one engine. Whereas ma engines needs only one boiler.'

Mr Hornblower was almost reassured that he had indeed bought the best engine before he left on business at another mine. 

 The rest of us went to see Tin-Tang. It was cold and windy and, as we approached the mine, low scudding clouds brushed the tree tops and the air was damp. The first thing we saw was a clutter of sheds with a tall, narrow brick building looming over them. The building might have been a church tower except for its steeply pitched grey slate roof and a huge wooden beam that leaned out of a hole near the top of one wall. On the end of the beam was an arc shaped structure with a chain dangling from it. The wind whipped away a plume of smoke from a chimney above the rooftop. As we approached, the building emitted a strange asthmatic wheezing and the beam moved up.

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