V. MANUFACTURES. 653 



2719. No. 2. Silicate of Soda (glass), suitable for calico 

 printing. William Gossage Sf Sons. 



Composition : 



100 parts, Na^O. 

 310 SiOj. 



2720. No. 3. Silicate of Potash (glass). 



William Gossage S>- Sons. 

 Composition : 



100 parts, K 2 O. 

 310 SiO 2 . 



2721. No. 4. Solution of Alkaline Silicate of Soda, made 

 from No. 1. 1,500 specific gravity. William Gossage 3? Sons. 



2722. No. 5. Solution of Silicate of Soda, 1,375 specific 

 gravity. Made from No. 2. William Gossage Sons. 



2723. No. 6. Solution of Silicate of Potash, 1,350 specific 

 gravity. Made from No. 3. William Gossage fy Sons. 



2738f. Examples of Technological Diagrams. 



Diagram 6. Retort for the manufacture of coal gas. 



55 ' '5 5> 



5, 28. Extraction of zinc (Silesian furnace). 

 ,, 31. Lime-kiln (continuous* process). 



32. Lead smelting (German cupellation hearth). 



36. Lead smelting blast furnace. 



37. Extraction of salt by evaporation of brine. 



Graduation house. 



50. Manufacture of steel by cementation. 



The Council of the Yorkshire College of Science, Leeds ; 

 Prof. Thorpe. 



24:60. Oxalic Acid. Two specimens. One crystallised from 

 a solution containing sulphuric acid, the other ;from an aqueous 

 solution. Roberts, Dale, Co. 



This product is made by the action of caustic potash, or a mixture of 

 caustic potash and caustic soda on woody fibre (sawdust). The result of this 

 action is oxalate of potash. The oxalic acid is isolated by precipitation as 

 oxalate of lime, and the subsequent decomposition of this latter product by 

 sulphuric acid. Specimen No. 2 is crystallised from water. A comparison 

 will show the marked difference in crystalline form due to the presence of 

 sulphuric acid. 



2461. Binoxalate of Potash. Roberts, Dale, $ Co. 



