122 Mr. T. Richardson's Researchet 



These ashes, treated with muriatic acid, afforded not the 

 slightest perceptible trace of carbonic acid. When they were 

 boiled with carbonate of soda, the clear filtered solution of 

 the same, saturated by nitric acid, produced not the smallest 

 milkiness with a salt of barytes. 



Carbon and Hydrogen. 



The estimation of the carbon and hydrogen was partially 

 made by means of oxide of copper, but generally with melted 

 chromate of lead. The apparatus was perfectly the same as 

 that employed by Professor Liebig, the only difference being 

 in the use of the above salt. A more exact account of the 

 employment of this substance will be found in another me- 

 moir. 



Azote. 



With respect to the method employed in the determination 

 of the azote, it will be necessary to enter more minutely into 

 particulars (though perhaps a digression from the proper sub- 

 ject of the present memoir,) to show that no exertions on my 

 part have been wanting to obtain an exact result. Five or six 

 analyses were made with the apparatus which Professor Lie- 

 big has already described for the absolute estimation of azote. 

 The azote in all the analyses amounted to nearly 4 per cent. 

 When it is remembered what a small quantity of sal ammo- 

 niac is obtained in every gas manufactory, this amount will at 

 once appear much too great. 



The method of determining the azote by means of its rela- 

 tion to the carbonic acid was then resorted to, but it was 

 found impossible to measure the volume of the azote. I could 

 only in this way guess at the true quantity of azote, and it 

 appeared to be as 1 H : 100 COg. 



At the suggestion of Professor Liebig, the following plan 

 was then pursued : — The apparatus, as per diagram, (Plate 

 in.) consisted of an ordinary tube of combustion a, about 20 

 inches long, and from '4 to '5 inch diameter, connected with 

 a tube b, having 2 balls, and about 10 inches long and '4 inch 

 in diameter. A small thermometer tube c was united to the 

 other part of the apparatus by means of a piece of caoutchouc, 

 and conducted the gas into a receiver d, which was partially 

 filled with mercury. A part of the tube c remained always 

 above the level of the mercury in the receiver d. 



The tube of combustion a contained in the hermetically 

 sealed end from 2 to 2^ inches of hydrate of lime, then one 

 inch oxide of copper, afterwards the mixture of the substance 



