12 



hand wheel right or left it will be seen that, by the method 

 exhibited, the boiler is able to modify its form without strain- 

 ing, and consequently without danger. 



21. Fox, Head, & Co.'s patent puddling furnace, Mid- 

 dlesbrough-on-Tees, England. 



An improved furnace for puddling iron. 



1876. Lent by Jeremiah Head, M.I. C.E. 



The object is to utilise a portion of the waste heat which 

 ordinarily is discharged from the chimney, by causing it to heat 

 air to be afterwards supplied for the combustion of the fuel. 

 Part of the chimney is enlarged into a chamber, having a vertical 

 partition extending nearly to the top. One half of the chamber 

 thus divided contains a cast-iron stove pipe, and the other half is 

 provided with a damper. 



When the damper is withdrawn the heated products of com- 

 bustion take the nearest route to the chimney, but when it is 

 closed they are obliged to pass by the more circuitous route, 

 heating the stove pipe on the way. 



The air for combustion is injected, by means of a steam jet, 

 into a funnel connected with one side of a divided box, upon 

 which the stove pipe stands. Moistened with the steam it 

 becomes a powerful absorber and radiator of heat. It passes 

 through the heated stove pipe, and afterwards through the back 

 of the furnace into a closed ash-pit, and a portion through 

 tuyeres into the space above the fuel. 



It has then attained a temperature of about 650 Fahr. 

 The consumption of coal of this furnace has averaged 

 12 cwt. 2 qrp. 11 Ibs. per ton of puddled bar over two months of 

 ordinary work, including lighting up and lost heats. This is 

 about one half of the usual consumption of fuel. The iron 

 (refined) used per ton of puddled bar in the same time averaged 

 20 cwt. 2 qrs. 26 Ibs. The heating chamber is surmounted by 

 a boiler, intended still further to utilise the waste heat. This, 

 however, is not essential, and is hardly worth the extra expense. 

 An ordinary iron- cased chimney is preferable. 



22. Drawing of Siemens' rotative furnace for the pro- 

 duction of wrought iron. 



1876. 



23. Model of a double iron-fining ground forge with 

 double blast, smoke shaft, &c. From the series of 

 models intended for technical instruction. 



E. 127. 1868. Made by J. Schroeder, Darmstadt. 



24. Diagram of Price's retort furnace. 



1876. Lent by W. Price. 



