72 Dcebereiner'' $ Eudiometer. 



to whom, on the 20th of September, Prof. Dcebereiner com- 

 municated his remarks and experiments." 



From Schweigger's Journal for November, we accordingly 

 extract the following : — 



"At a meeting of the Society of the Explorers of Nature, 

 held on the 20th of September 1823, Professor Dcebereiner 

 fulfilled the promise he made at the first meeting ; viz. to com- 

 municate something more respecting his new and important 

 discovery, so far as it is applicable to eudiometry, and to ex- 

 hibit it by experiments. 



" The platinum is kneaded up with clay into small balls, which 

 are then brought to a white heat before the blowpipe. If such 

 a ball, suspended by a platinum-wire, is dipped into an open 

 glass vessel filled with hydrogen and oxygen, the ball rapidly 

 becomes red-hot ; during which a cloud of vapour forms itself 

 around it ; it then becomes white-hot, and the explosion im- 

 mediately takes place. Such balls answer best for eudiometri- 

 cal experiments made over quicksilver. The decomposition 

 would certainly not be completely effected if the platinum-pow- 

 der, moistened by the water which is formed, ceased to remain 

 hot. But how easy is it in such a case to let another ball be 

 carried through the quicksilver, in case the first is not sufficient !" 



No. XXXII. of the Quarterly Journal of Science contains 

 the following article on the same subject : — 



" Professor Dcebereiner has suggested the use of finely divided 

 platina for the purpose of detecting minute portions of oxygen 

 in a gaseous mixture, in which hydrogen also is present. Its 

 effect is immediate ; the moment the substance rises above the 

 surface of the mercury in the tube containing the mixture, 

 the combination of the oxygen and hydrogen begins, and in a 

 few minutes is completed ; and, as Professor D. has stated, it 

 seems capable of detecting the smallest quantity of oxygen. 

 Its utility in the analysis of atmospheric air, and compounds 

 containing oxygen, is obvious, provided no combination also 

 takes place between the hydrogen in excess, and the nitrogen 

 (or other gas) that may be present, as does in fact happen, ac- 

 cording to Dcebereiner, when protoxide of platinum is so em- 

 ployed. 



" Messrs. Daniell and Children mixed 20 measures of atmo- 

 spheric air with 37 measures of hydrogen gas, and passed up 

 to the mixture a small portion of the platina powder, procured 

 by heating the ammonia muriate to redness, and made into a 

 ball with precipitated alumina. The pellet was heated red by 

 the blowpipe, immediately before it was used, its size about 

 that of a small pea. The absorption amounted to 1 3 mea- 

 sures = 4.3 oxygen, being 0.1 of a measure more than the 

 quantity of oxygen in 20 measures of atmospheric air, which 



may 



