134 THE WATT AND THE TREVITHICK ENGINES. 



Docks. It will be ready to send off to London in about four 

 weeks. It will be a very complete engine. The pumps for 

 forcing the water will be fixed on the back of the boiler. It 

 will force 500 gallons of water 100 feet high in a minute ; above 

 ten times the quantity that engines worked by men can do. 

 Mr. Homfray and myself shall be in town as soon as the 

 castings are sent off. I hope you will be there at the time. If 

 you wish to see the engines already at work in London, call on 

 Mr. David Watson, steam-engine maker, Blackfriars Koad. He 

 lives up about 500 or 600 yards above the bridge on the left- 

 hand side; you will see his name over his door. If you have 

 time to inspect those engines you will find by comparing them 

 against Boulton's, doing the same work, that there is a 

 great saving of coal above other engines. ... I shall go to 

 Liverpool and Manchester from here, and again to Coal- 

 brookdale. 



" There are three engines at the Dale begun, to work with 

 condensers, for places where coal is scarce. I think it is better 

 to make them ourselves, for if we do not, some others will, for 

 there must be a saving of coal by condensing. But with small 

 engines, or where coal is plentiful, the engine would be best 

 without it. They say at the Dale about putting two cylinders, 

 but I think one cylinder partly filled with steam would do 

 equally as well as two cylinders. 



" That engine at Worcester shuts off the steam at the first 

 third of the stroke, and works very uniformly. I cannot tell what 

 coal it burns yet, but I believe it is a very small quantity. I 

 shall know in a short time what advantage will be gained by 

 working expansive. I expect it will be very considerable. 

 There are a great many engines making and ordered. Boulton 

 and Watt and several others are doing everything to destroy 

 their credit, but it is impossible to destroy it now that it is so 

 well known. I have not taken any of the ground at Bristol to 

 remove. I called on them and told them it was possible to 

 break the ground without men, and they wish me to take a 

 piece to clear out, but would not set but a small piece at a 

 time ; therefore it would be disclosing the business to no pur- 

 pose. They were very desirous to know the plan, but I would 



