The Rev. J. E. Ashby on Catalytic Pkanomena. 53 



3. AgO, reduced to metallic silver, which shows a strong ten- 

 dency on gauze, and acts perfectly in the combustion-tube. 



4. U, O3, HO became, at red heat, anhydrous mixture of U O 

 and UjO^, showing strong tendency. A very pure specimen cata- 

 lysed the vapour as it changed from yellow to green, after which it 

 died away. Will not act below 570° (F.). 



5. SnO ; strong tendency. 



6. SnO,,; slight tendency. 



7. WO.j a])parenthr produces the effect if placed while glowing, 

 over alcohol, but gradually dies away, as if very slowly cooling. 



'8. Pbg O^ changed to PbO, and showed a strong tendency, but 

 quickly faded and grew cold. 



9. CdO, placed while very warm over pyroxylic spirit, burst into 

 glow and catalysed, but always died off after the lapse of from half a 

 minute to two or three minutes, and then became incapable. 



10. CaO (on the gauze), no effect. 



11. SiO., exhibited a tendencjr. 



1 2. Stourbridge clay ; no effect. 



13. AL, O3 appeared to have no effect in maintaining catalytic 

 combustion on the gauze, but when made red-hot and quenched in 

 absolute alcohol, it changed from pure white to a black substance 

 and oxidized a portion of the alcohol. That this is not owing to 

 carbon in the alcohol is evident, because the same change occurs 

 when it is quenched in strong liquid ammonia. I suspect that it is 

 a new oxide of aluminum. 



14. Nij O3, formed by heating carbonate of nickel nearly to red- 

 ness, failed ; prepared from the common nitrate, it acted for a short 

 time ; reduced as an intensely black velvety substance from the purest 

 nitrate, then warmed but not made red-hot, it glowed and catalysed 

 with alcohol or ether. With pyroxylic spirit, it was left at the end 

 of the operation of a greenish drab, which I suspect to be a mixture 

 of Ni^ O3 with NiO, although it may be Ni., O., changed only in ap- 

 pearance, for when treated with nitric acid no nickel is dissolved. 



15. Mn O., is changed at red heat into Mn., O3, which, with alco- 

 hol, ether, and pyroxylic spirit, continues the slow combustion very 

 steadily. A s])ecimen of very pure Mn^, O.j acted extremely well, as 

 did also a portion of " euchrome " (a hydratcd sesquioxide of man- 

 ganese (impure) dug from the estate of Lord Audley), after being 

 heated in the air to drive away the carbonaceous matter with which 

 it was mingled. Mn., O., will, if sufficient care betaken, catalyse 

 the moist gas arising from a strong solution of ammonia. 



16. Fe.j O.,, when in the state of a light puffy powder, catalyses the 

 vapour of ether, alcoliol, and pyroxylic sj)irit, only requiring to be 

 heated on the gauze before it is laid over the capsule. It is cheap, 

 easily employed, and of invariable action. I have kept up the com- 

 bustion for several hours on a surface of 120 square inches. 



By means of a catalytic lanij) in which the liquid employed is con- 

 tinually supplied from a reservoir and maintained at a constant level 

 in the capsule, I have used 7 or S square inches continuously during 

 thirty-six houi,-. This lamp I have occasionally used for laboratory 



