Dr. R. D. Thomson's ExaminaJtvon of the Cowdie Pine Besm. 126 



I. 9-435 grs. gave 25-71 grs. CO,, and 8-73 grs. HO. 

 II. 5-G9 do. 15-565 grs. C0» 

 Hence wo have — 



L II. Mean. 



Carbon 74-30 74-60 74-45 



Hydrogen, .... 10-28 10-28 



Oxjgen, 15-42 1527 



100-00 10000 



To determine whether the resin was sufficiently dried, a portion 

 was fused and exposed to a temperature of 350° for some time. The 

 following were the results of two analyses : — 



I. 6-97 grs. gave 19-30 grs. CO^, and 6-18 grs. HO. 

 II. 7-96 do. 6-93 grs. HO. 

 This is equivalent to — 



I. II. Mean. 



Carbon, 75-46 75-46 



Hydrogen, .... 9-85 9-67 9*76 



Oxygen, 14-69 14-78 



100-00 100-00 



From these data we may deduce the following composition : — I use 

 -75 for carbon ; — that being the number employed by Dr. Thomson 

 since 1813, as deduced by him from the specific gravity of carbonic 

 acid and composition of defiant gas. The number of Professor Liebig 

 (•758,) is so near this that the formula will scarcely be altered by the 

 use of the latter number. 



Calculation. Experiment. 



Carbon, ... -75 x 40 = 30- = 75-23 75-46 



Hydrogen, . . -125 X 31 = 3-875 = 973 976 



Oxygen, ... 1- x 6 = 6- = 1504 14-78 



39-875 10000 100-00 



The close correspondence of the theoretical and practical results in 

 reference to the hydrogen, may lead us with some degree of confidence 

 to assume the following formula, as representing the composition of 

 the Cowdie Resin 



C^o H31 Ofi 



and adopting an analogous view to that of Professor Liebig, in refer- 

 ence to the composition of turpentine resins, we may consider the 

 basis of the resin 



Cit Haa g 



becoming by the substitution of one atom of oxygen, and the addition 

 of 5 atoms of oxygen, 



C« H^ 0+^» 



No. 7. 2 



