368 GIBBS. 



sulphuric acid on pure zinc in a Kipp apparatus. From the generator it was 

 passed through a solution of pyrogallol in caustic potash, concentrated sulphuric 

 acid, tubes of soda lime and calcium chloride, a combustion tube of copper turnings 

 and copper gauze heated to redness and finally a wash bottle of pure, concentrated 

 sulphuric acid, from which it was led directly into the tubes in which the experi- 

 ments were to be conducted. 



The nitrogen was obtained by passing atmospheric air through five large wash 

 bottles, each holding several liters of alkaline pyrogallol and then through tlie same 

 train of apparatus used in purifying the hydrogen. Other indifferent gases of 

 the atmosphere were, of course, present. The carbon dioxide was generated in a 

 Kipp apparatus by the action of hydrochloric acid on marble. It was purified by 

 passing through a calcium chloride tower and a wash bottle of pure concentrated 

 sulphuric acid. 



The phenol used was a pure sample beautifully crystallized. The crystals were 

 removed from the bottle by means of platinum tipped forceps and transferred 

 directly to the glass tube through which a rapid current of gas was passing. The 

 form of tube employed and the method of sealing in the required gas so as to 

 exclude all atmospheric air was that employed by Franklin '' in his work with 

 ammonia with the exceptions that no stopcocks were used on the tubes and at 

 atmospheric temperature the interior of the sealed tubes were at atmospheric 

 pressure. 



The following ten. tubes and no others comprise this investigation : 



I. Phenol (about 2 grams), freshly boiled water 3 drops, sealed in a hydro- 

 gen atmosphere. 



II. Phenol (about 2 grams), freshly boiled water 1 cubic centimeter, heated 

 to boiling in a hydrogen atmosphere and then sealed. 



III. Same as I, except sealed in nitrogen. 



IV. Same as II, except sealed in nitrogen. 



V. Same as I, except sealed in carbon dioxide. 

 VI. Same as II, except sealed in carbon dioxide. 

 VII. Phenol (about 2 grams), water 3 cubic centimeters, boiled in a carbon 

 dioxide atmosphere and sealed. 



VIII. Phenol (about 3 grams), boiled in a carbon dioxide atmosphere and 

 sealed. 



IX. Same as I, except sealed in atmospheric air. 

 X. Same as II, except sealed in atmospheric air. 



These tubes were then placed in the direct sunlight and constantly 

 agitated by means of a mechanical device. 



Tubes IX. and X showed a distinct color in a short time and were a 

 light red color in two hours. The color, as nearly as can be judged by 

 the eye, deepened constantly for about ten days. These two tubes are 

 the only ones which show any color visible to the eye. At this writing 

 they have been exposed to the sunlight for fifty-seven days. This work 

 confirms that of Kohn and Fryer. 



Since phenol and moisture sealed in this way in an atmosphere of an 

 indifferent gas will form a delicate test for the presence of oxygen, 

 tubes V, VI, and VII produce evidence that carbon dioxide and water 



^J. Am. Chem. Soc. (1905), 27, 831. 



