13 



25. Model, after Karsten, of a lead-smelting furnace, 

 with coal firing. From the series of models intended 

 for technical instruction. 



E. 128. 1868. Made by J. Schroedcr, Darmstcdf. 



26. Photograph of the general plan of the quicksilver 

 mines of Almaden, Spain. Made in 1796, by Dr. Diego 

 Larrafiaga. 



1876. 



Presented by the Royal School of Mines, Madrid. 



27. Photograph of a plan, made in 1830, by Dr. V. 

 Romoro, of Watts' steam engine, which was used at the 

 mines for extracting water. 



1876. 



Presented by the Royal School of Mines, Madrid. 



28. Photograph of a plan of some quicksilver furnaces. 

 1876. 



Presented by the Royal School of Mines , Madrid. 



29. Photograph of plan, outline, and sections of the 

 boilers of the steam engines used in the quicksilver mines 

 at Alinaden, drawn by Vicento Romoro, in 1830. 



1876. 



Presented by the Royal School of Mines, Madrid. 



30. Model of a coking furnace, after Scheerer. 



E. 131. 1868. Made by J. Schroeder, Darmstadt. 



31. Model of a coking furnace. 



E. 133. 1868. Made by J. Schroeder, Darmstadt. 



32. Diagrams of Bull's patent semi-continuous kiln for 

 coking (2). 



1876. Lent bij H. Wedekind. 



33. Model of Simon-Carves' coke oven. 



E. 67. 1888. Made by H. Simon. 



In this oven the coal is coked in comparatively thin layers, the 

 heat being obtained by the combustion of the products of distil- 

 lation of the coal in spaces around the walls of the coking 

 spaces. 



