i86 Prof. Berzelius and Dr. Marcet's Experiments 



tube. In order to separate these two gases from each other, 

 we made use of the brown oxyd of lead, a substance which 

 one of us had often employed for the purpose of combining 

 with, and separating from other bodies, liquid sulphureous 

 acid, with which that oxyd forms a neutral sulphate. The 

 same method, to our great satisfaction, succeeded perfectly 

 with the gaseous sulphureous acid. After a contact of about 

 one hour, between the brown oxyd of lead and our mixed 

 gases, the whole of the sulphureous acid gas was so com- 

 pletely absorbed, that the carbonic acid gas which remained 

 in the vessel, had not the least sulphureous smell, and yet the 

 carbonic acid itself remained perfectly unaltered in its bulk, 

 after continuing in contact with the oxyd of lead for the space 

 of three days.* 



8. The mode in which the respective weight of the two 

 acids was ascertained was this; the oxyd of lead was placed in 

 a small glass capsule (^, fig. 2), the orifice of which was care- 

 fully secured, by means of a thin piece of glove-leather, against 

 the admission of quicksilver. A very thin flexible metallic 

 wire was fastened to the capsule, so as to enable the operator 

 to raise it through the mercury in the receiver containing the 

 gases, as is expressed in the figure (fig. 2). After continuing 

 the contact for several hours, and when the absorption had 



* The brown oxyd of lead, used in our experiments, was recently prepared, and 

 had been long digested in weak nitric acid. In wiping this oxyd, and pressing the 

 moisture out of it, we found it expedient to reduce it to the state of small laminae, as in 

 this form it is more easily penetrated by the acid gas than in the state of powder. It 

 may be proper to remark, that when, for the sake of trial, gaseous mixtures, consist- 

 ing of sulphureous acid gas and sulphuret of carbon in vapour, were used, the latter, 

 as the absorption of the acid gas proceeded, was deposited in its liquid state upon the 

 oxyd of lead. 



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