II. TEACHING (PURE). oUJ 



2456b. Two Bischof's Evaporating Apparatus to use for 



Frankland's .apparatus. One graduated nitric acid tube. Enamel 

 back. E. Cetti $ Co. 



2456c. Water Quick Filter Pump for use with a fall of 40 

 feet. E. Cetti $ Co. 



2456d. Set of Russell and West's Apparatus for estimating 

 the urea in urine. E. Cetti fy Co. 



2456e. Six Burettes and Scale Pipettes, with registered 

 enamel back to show up the divisions. E. Cetti 8? Co. 



2456f. Tube with Beads to collect the Ammonia in Coal 



Gas as used at the testing stations. E. Cetti fy Co. 



2456g. Nessler's Tubes for Colour Test. E. Cetti $ Co. 



2456H. Cavendish's Eudiometer. E. Cetti fy Co. 



24561. Ure's Eudiometer. E. Cetti $ Co. 



2456k. Mitscherlich's Eudiometer. E. Cetti $ Co. 



2520. Fixed appliance for the analysis of gases with three 

 reagents. M. Or sat, Paris. 



2521. Fixed appliance for the analysis of gases with two 

 reagents. M. Orsat, Paris. 



2522. Portable Appliance for the analysis of gases, giving 

 the quantity of gases, giving the quantity of the hydrogen and its 

 carburets. M. Orsat, Paris. 



2523. Stand used in chemistry for the fusion of metals by 

 means of a gas apparatus. 



2524. Laboratory Forge, with double draught, fitted with a 

 cerfeu for the fusion of metals. 



With this forge the pressure can be increased by reducing the quantity of 

 air when soldering is required, either with gas, or with Mr. Sainte Claire 

 Deville's forge lamp, or with Mr. Schlosing's blow pipe. 



2525. Apparatus for regulating the Pressure of Gas. 



Prof. A. Crum Brown. 



The apparatus consists of a gasometer, the pressure of the gas in which 

 depends upon the weight of the inverted vessel and that of the counterpoises. 

 The peculiarity of the arrangement lies in the mode in which the gas is intro- 

 duced into the gasometer. The gas is led from the main or meter to a fixed 

 vertical tube, and thence by a short piece of india-rubber tube to a metal 

 tube fixed to one of the counterpoising weights, and from that tube to the 

 gasometer. When the pressure in the main increases the vessel rises, and the 

 counterpoise falls ; the short india-rubber tube is thus bent, and the entrance 

 of gas into the gasometer hindered. This short india-rubber tube is thus a 

 self-acting valve, always admitting exactly the same quantity of gas as is 

 drawn off from the gasometer. 



39508. - K k 



