COAL-TAR AND WATER-GAS TAR CREOSOTES. 



97 



Condenser. — A copper trough condenser shall be used with straight-walled glass 

 tube, having approximately the form and dimensions shown in figure 46. 



Separatory funnel. — A separatory funnel of the form shown in figure 46 shall be 

 used, having a total capacity of 120 c.c, and the outlet graduated in fifths of a cubic 

 centimeter. 



The apparatus shall be set up as shown in the figure. 



When any measiu-able amount of water is present in the distillate below 210° C. on 

 testing in accordance with the distillation, the oil and water in this fraction shall be 

 separated, if possible, and measured separately. If more than 2 per cent of water is 

 present, or if the water is apparently present to an extent in excess of 2 per cent, but 

 an accurate separation is impossible, the percentage of water present shall be deter- 

 mined by the following method, and the water-free oil so obtained shall be used in 

 the distillation test: 



Measui'e 200 c.c. of oil in graduated cylinder, and pour into copper still, allowing 

 the cylinder to drain into the still for several minutes. Attach lid and clamp, using 



Cos Pip' 



Sapororor/ Funna/ 



Fig. 46. — Apparatus for determining moisture content of cersote oil. 



a paper gasket slightly wet with oil around the flange of the still. Apply heat by means 

 of the ring bvirner, which shall be placed just above the level of the oil in the still at 

 the beginning of the test, and gradually lowered when most of the water has distilled 

 over. Continue the distillation until the vapor temperature, indicated by the ther- 

 mometer with the bulb opposite the offtake of the connecting tube, reaches 205° C. 

 Collect distillate in separatory funnel. When the distillation is completed, and a 

 clear separation of water and oil in the funnel has taken place, read the water by 

 volume and draw off; and return any light oil distilled over with the water to the oil 

 in the still. The dehydrated oil from the still shall be used for the distillation test. 



TEST OF THE SPECIFIC GRAVITY OF THE FRACTIONS. 



The test of the specific gravity of the fractions has been adopted 

 by the American Wood Preservers' Association, the American Society 

 for Testing Materials, and the American Railway Engineering Asso- 

 ciation. Tests that may be applied to the fractions obtained in the 



75536°— 22 7 



