y=- 



(22) 



194 M. R. Bunseu on the Law of Absorption of Gases. 



The sum of these two equations gives the value of a, their differ- 

 ence that of ft. 



By help of these values a. and /3, we obtain, lastly, — 



__ (g 3 — a + «& 2 ) (g a + ffio) 



**.(«-£) 



■-«-* (23) 



As an example of such a calculation, I select the qualitative 

 and quantitative determination of the gas prepared by heating 

 oxalic acid with concentrated sulphuric acid. As this gas always 

 contains small quantities of sulphurous acid mixed with it, it 

 was first passed through water in which binoxide of manganese 

 was suspended, and the gas collected after the water had been 

 saturated, and the atmospheric air contained in the apparatus 

 displaced. A eudiometric analysis of the purified gas gave, — 



Carbonic oxide 

 Carbonic acid 



Found. 

 5006 

 49-94 



Calculated. 



5000 

 50-00 



100-00 100-00 



The absorptiometry determination, which was conducted in 

 such a manner that the amount of absorbing water was in- 

 creased after every observation, gave the following element : — 



From these elements, the value of /3 is found by means of 

 formulas (20) and (21) to be 0-9248. The tables of absorption 

 show that carbonic acid gas has for the observed temperature a 

 corresponding absorption-coefficient ; for the table gives for this 

 gas the number 0-0150, which closely approximates to the ex- 

 perimental coefficient /3. We conclude from the constitution of 

 a precipitate, from its colour, from its solubility, &c, that a 

 certain substance is present. It is here not a precipitate, but 

 a certain ordinate of a solubility-curve which serves as our test. 

 But as there are certain precipitates produced by different sub- 

 stances resembling each other so closely that they cannot be 



