636 . SEC. 13. CHEMISTRY. 



System of convergent lines, etched on glass, for making divi- 

 sions. 



Hydrogen generating apparatus. 



Apparatus for measuring the rapidity with which gases issue 

 through a narrow aperture. 



Spectroscope. 



Spectroscope, provided with micrometer movement for the two 

 telescopic tubes, an eccentric movement for the adjustment of the 

 observation telescope, comparison prisms, cross-thread, &c. 



Pocket spectroscope. 



Universal clamp. 



Stand for holding flasks, &c. 



Stand for holding Geissler's tubes. 



Stand for holding carbon points. 



2 stands provided with adjusting screws. 



2 stands provided with three legs. 



3 holders for burettes. 



6 rings of different sizes. 



6 filtering rings of different sizes. 

 2 forks. 



7 clamps. 

 Photometer. 



r^ 11 



Gas-clock. 

 Test-tube holder. 

 2 water bathe, 2 sizes. 

 Apparatus for regulating the level of water. 

 Bunsen's gas regulator. 

 Drying apparatus. 

 Apparatus for showing the reversal of the sodium spectrum. 

 Several cases containing chemical substances for practising 

 spectroscopic analysis. 



Chimneys for the various lamps, 15 different sizes. 



2574b. Doberawer's or Philosopher's Lamp. 



Parkinson $ Frodsham. 



This lamp when charged with dilute sulphuric acid is self -igniting ; it 

 suffices to raise the arms of the small figure, and the spongy platinum 

 then brought into view, becomes incandescent. The explanation of this 

 is that the hydrogen generated in the body Of the lamp, which con- 

 tains zinc, is drawn into such close contact with the oxygen of the air, by 

 reason of the extreme fineness of the spaces between the particles of the 

 platinum, that the two .gases combine chemically, or in other words burn, 

 whereby sufficient heat is generated to raise the temperature of the platinum 

 to a red heat, sufficient to ignite paper, &c. 



2572a. Heating Apparatus for Laboratories. 



M. Wiesnegg, Paris. 



1. (?) Arched Bunsen burner. 



2. Plain Bunsen burner, with support. 



