CHEMICAL SCIENCE. 235 



of temperature. The mixture is to be allowed to stand a day, then 

 distilled from two parts by weight of binoxalate of potash. A volatile 

 fluid at first passes over, after which the oxalate of methyl condenses 

 in the neck of the retort. The receiver is now to be changed and the 

 distillation continued as long as the ether comes over. The neck of 

 the retort is then to be gently warmed and the oxalate allowed to flow 

 into the receiver when it is to be strongly pressed between folds of 

 bibulous paper, and then freed from volatile products by long fusion. 

 In this way it is obtained directly perfectly colorless. The liquid 

 which passes over first contains also oxalate of methyl which is readily 

 obtained by evaporation and crystallization. The pure oxalate of 

 methyl prepared in this manner is now to be distilled with water ; 

 mre wood-spirit passes over and oxalic acid remains in the retort. 

 'This method obviously presents great advantages over the tedious 

 processes of Dumas and Kane.] Ann. der Chemie und Pliarmacie, 

 \ xxxi. 



FORMATION OF SULPHURIC ACID FROM SULPHUROUS ACID AND 



OXYGEN. 



WOHLER has published a few observations relating to the formation 

 of sulphuric acid, which, although involving no new principle, promise 

 to be of great importance in a manufacturing point of view. The 

 action of spongy platinum at a high temperature upon a mixture of 

 sulphurous acid and air or oxygen, has long been known. A patent 

 was even granted to Peregrine Phillips for the manufacture of sul- 

 phuric acid by this process, the anhydrous acid formed being condensed 

 and united to water in an appropriate receiver. The method was 

 however abandoned as a more extended experience showed that the 

 platinum speedily lost its power of condensation. Wohler has now 

 found that various metallic oxides possess in a high degree the property 

 of causing the union of mixed gases. When the oxides of copper, 

 iron, or chromium, are heated to a low Redness in a glass tube and a 

 mixture of sulphurous acid and air or oxygen is caused to pass over 

 them, thick white A^apors of anhydrous sulphuric acid are formed. A 

 mixture of the oxides of chromium and copper prepared by precipi- 

 tation was found to be particularly efficient ; the same quantity of 

 oxide appeared capable of converting an unlimited quantity of the 

 mixed gases into sulphuric acid, and the production of sulphuric acid 

 was so easy and rapid as to lead to the idea of practical application on 

 a large scale. Metallic copper in a state of powder produces sulphuric 

 acid in a similar manner, but only when heated and when its surface 

 has become converted into oxide. No hydrate of sulphuric acid is 

 formed by passing the vapor of water over the oxide at the same time 

 with the gaseous mixture. Platinum foil polished and cleaned acts 

 upon the gaseous mixture like spongy platinum, but not at ordinary 

 temperature. A mixture of the oxides of copper and iron prepared 

 by precipitation and ignited, becomes and remains incandescent when 

 21 



