OP ARTS AND SCIENCES. 489 



acid, phenolplithalein being used as an indicator. The oxalic acid 

 used contained 2.8636 grams of pure crystallized oxalic acid to the 

 litre, and one centimeter of the solution was therefore equivalent to one 

 milligram of carbonic dioxide. While it was evident that any volatile 

 acids formed and carried into the baric hydrate would be counted as 

 carbonic dioxide, direct experiments convinced us that the error intro- 

 duced in this way, even at the higher temperatures employed, was 

 inappreciable. For convenience in the comparison of our results we 

 have in each case calculated the number of milligrams of carbonic 

 dioxide directly and indirectly formed in one hour from each gram 

 of wood. 



Our first series of experiments was made with sound pine wood. 



I. 2 grm. of wood when heated for 1 hour at 220° gave 13.35 mg. 

 direct and 3.5 msr. indirect CO.,. 

 II. 2 grm. of wood when heated for 2 hours at 200° gave 10.6 mg. 

 direct and 4.1 mg. indirect COj. 

 III. 2 grm. of wood when heated for 2 hours at 180° gave 3 mg. 



direct and 1.8 mg. indirect COg. 

 IV. 2 grm. of wood when heated for 3 hours at 162° gave 2.6 mg. 



direct and 2.1 mg. indirect COj. 

 V. 2 grm. of wood when heated for 5 hours at 143° gave 1.7 mg. 



direct and 2 mg. indirect COj. 

 VI. 2 grm. of wood when heated for 7 hours at 123° gave 1.3 mg. 

 direct and 2.8 mg. indirect CO2. 



Sound Pine Wood. 



Milligrams of CO2 in one Hour for 

 each Gram of Wood. 



Direct. Indirect. 



6.67 1.75 



2.65 1.03 



0.75 0.45 



0.43 0.35 



0.17 0.20 



0.09 0.20 



In order to determine whether the indirect carbonic dioxide was 

 formed wholly or in part from the volatile constituents of the wood, 

 which were volatilized without decomposition, two successive deter- 

 minations were made at the same temperature, with the same sample 

 of wood and the products formed determined as before. 



