28 WOOD TURPENTINE. 



Further, it should be no more deleterious to the health of the work 

 man than the gum spirits. 



The refining experiments conducted in this laboratory have beei 

 controlled by determining the specific gravity, refractive index, initia 

 boiling point, and behavior on distillation of samples drawn at statec 

 times during the refining operations and of the several final product* 

 obtained from these operations. 



USE OF THE PERIODIC COLUMN STILL. 



The refining experiments on an industrial scale have been madt 

 with pot stills and two forms of periodic columns, which are showr 

 in sections in figures 3 and 4. Figure 3 is an ordinary beer still o: 



10 chambers, such as is used in making alcohol, modified and adaptec 

 to the work. Both columns were used as periodic stills. The stearr 

 necessary to boil the crude turpentine is admitted to the botton 

 chamber of the column through the pipe 8. It boils the crude oils ir 

 this chamber and passes upward through one chamber after another 

 boiling the descending crude oil and carrying with it the turpentine 

 vapors. The plates within the column are perforated so as to allo\\ 

 the steam to pass through them. The vapors rise to the upper part 

 of this column and are conveyed through the pipe 9 into the heatei 

 3, where they are circulated about the tubes containing the crudt 



011 passing through the heater, and then are carried through the pipe 

 10 into the condenser 11 and thence to the separator 13 through th< 

 test box 12. 



The crude turpentine is discharged from pump 1 and pipe 2 into 

 the heater 3. This heater contains a series of tubes through which 

 the turpentine is passed and around which the vapors coming from 

 the boiling oils in the column on their way to the condenser are cir- 

 culated. The heated turpentine leaves the heater through pipe 4 

 and reenters the column below the heater where it comes in contacl 

 with steam. The lower part of the column is divided by plates into 

 a series of chambers, in each of which the turpentine is boiled and 

 relieved of some of its light oils. The crude oil takes a downwarc 

 course through the drop pipes and across each of the various plates 

 It should lose all of its light oils by the time it reaches the bottom 

 chamber of the column, from which it is automatically dischargee 

 through valve 5, or subsequently distilled as pine oil, after the tur- 

 pentine has been removed. 



Figure 4 was also used as a periodic still in practically the same 

 way. The crude oils should flow from a storage tank into the 

 still through pipe 2. The column contains a series of chambers, 

 upon each of which is carried about 3 inches of liquid. A constant 

 level is maintained in each chamber by means of the drop pipes. 

 The plates between the chambers are not perforated as in figure 3, 



