30 



134. Diagrams (11) illustrative of mineral chemical 

 analyses after Fresenius. 



1879. By G. Desmazures, Paris. 



135. Brown's diagrams of apparatus, past and present. 

 In three frames. Compiled and drawn by J. F Brown 

 F.C.S. 



Sheets 1 and 2. Vapour densities. 

 Sheet 3. Regulators. 



1880. Given by J. T. Brown, F.O.S. 



136. Diagram showing the relative amount of organic 

 matter present in the water supply of London. 1868 to 

 1883. 



Lent by Dr. E. FranJcland, F.R.S. 



137. Diagrams of fittings fora chemical laboratory (4). 

 In frames. 



1883. Prepared for the Science and Art Department. 



138. Model of the Chemical Laboratory of the Secon- 

 dary Town School, Leyden. Constructed by J. Noest, 

 custodian of the building. 



Acquired from Dr. D. de Loos, Lecturer on Chemistry, 

 and Director of the Secondary Town School, Leyden. 

 E. 1. 1876. 



A. Forcing-pump. The pump fills a large cistern in the upper 

 part of the building. This cistern discharges its contents into 

 the white pipes, and supplies the laboratory and the other parts 

 of the building with water. The red pipes carry off the 

 drainage from the laboratory into a sink constructed below the 

 surface. The large black pipes, as also the small ones over the 

 pupil's work-tables, are the gaspipes. 



B. Kegister stove. 



C. Chimney with three passages ; one to conduct off the smoke 

 of the stove, the others to carry off the bad gases disengaged in 

 chemical operations. 



D. Pump for rain water and well water. 



E. Cupboards for twenty-two pupils, in which they keep re- 

 agents ; the largest, which is open, is for the use of the lecturer 

 on chemistry. 



F. Drawer for small apparatus, as spoons, glass tubes, &c. 



G. Small cupboards for the use of the pupils, in which to 

 keep chemical preparations still in progress. 



H. Bunsen's pump to filter under reduced pressure. The water, 

 running through the red pipe from the top to the bottom of the 

 laboratory, carries the air from the bottle along with it. 



I. Entrance to the balance-room. 



