8 VARIOUS INVENTIONS. 



sure will be as strong in the fire-place as in the boiler. The 

 whole of the air driven into the fire-place, with all the steam 

 raised by its passage up through the water in the boiler, must 

 go into the cylinder. There will also be the advantage of the 

 expansion of the air by the heat over and above what it was 

 when taken cold into the blast-cylinder. 



" From the great quantity of coal burnt in blast-furnaces you 

 will find that a very small blast-cylinder would work a 63-inch 

 cylinder double. If there is as much heat in a square foot of 

 air as in steam of the same temperature, the saving will be 

 beyond all conception ; but for my own part I cannot calculate 

 from theory what the advantages will be, if any, and for that 

 reason, before I drop or condemn the idea, I must request you 

 will have the goodness, when you have an hour to spare, to turn 

 your thoughts to this subject, and inform me of your sentiments 

 on it. 



" Perhaps it is like many other wild fancies that fly through 

 the brain, but I did not like to let it go unnoticed without first 

 getting your opinion. I hope you will excuse me for so often 

 troubling you. 



" St. Ives plans will be delivered to them on Tuesday, when 

 I expect they will be forwarded to you. 



"I hear there is a good course of ore in the adit end at 

 Wheat Providence Mine. 



" A Mr. Sheffield, of Cumberland, writes to Mr. Gould that 

 he has turned idle his air-furnaces, and smelted his ores by a 

 blast near a year since. 



" His furnace is but 10 feet high and 4 feet diameter, and it 

 melts 28 tons of ore, of from 4 to 5 in the 100 per week, and 

 makes a regel of from 65 to 70 in the 100, and answers beyond 

 what we calculated for them. 



"Suppose a furnace 20 feet high and 4 feet diameter, it 

 \vould smelt eight times the quantity of his, which would be near 

 900 tons per month, or nearly double the quantity raised by any 

 one mine in the country. The expense of the . . . would 

 be very trifling. 



" To-morrow Dolcoath account will be held, when I expect 

 to have orders to begin to erect a furnace on the spot. 



