204 BROOKS. 



suggestive of limonene. but he was unable to isolate the latter. He does not 

 state what variety of copal had this property. 



Wallach * subjected Kauri copal to destructive distillation and succeeded in 

 isolating pinene and dipentene. 



L. Schmolling °- examined the distillates from Kauri and Manila copals. The 

 oils from the latter resin were refractioned, but no terpenes nor any of their 

 characteristic derivatives were isolated. The aqueous portion of the distillate 

 gave reactions for formic and acetic acids. 



The Manila copal used in these investigations was selected from the 



first and second grades furnished by the Manila Trading and Supply 



30° 

 Company. The specific gravity (tco) varied from 1.060 to 1.067. It 



has been pointed out by Tixier 6 that it is impossible to assign definite 

 melting points to the copals. 7 Powdered Manila copal softens suffi- 

 ciently quickly to run together at about 100°. The freshly powdered resin 

 possesses a pleasant, aromatic odor which is probably due to limonene and 

 pinene, as will be shown in the experimental part of this paper. 



The Koettstorfer 'number, 8 obtained by boiling with alcoholic caustic 

 potash for one-half hour and using phenolphthalein as an indicator, 

 averaged about 160, being a little higher for the small pieces and chips 

 than for the large lumps. 



A study of the products given off by Manila copal during destructive 

 distillation up to the point at which the frothing ceases and the melt 

 is quite fluid has been made. It has been found that the decomposition 

 takes place in two stages. The first is characterized by much frothing 

 and the temperature of the mass rises slowly to about 330°, when it 

 becomes fluid and appears to boil quietly. At this point the loss in 

 weight is usually from 12 to 14 per cent of the original sample. The 

 soft, white pieces suffer a. greater loss in weight than the very hard 

 ones, due to the larger amount of volatile oils contained in them. The 

 temperature of the gases entering the condenser usually does not exceed 

 200° until the temperature of the melt reaches about 340°, at which 

 point resin oil begins to distill over in large quantities. The temperature 

 of the gases then quickly rises to about 330° and continues to rise slowly 

 as higher boiling resin oils distill over. High-boiling resin oils are 

 also carried over as a heavy mist with the gases which are rapidly 

 evolved. 



4 Arm. d. Chcm. {Liebig) (1892), 271, 308. 



'Chem. Ztg. (1905), 29, 955. 



"Journ. Soc. Chem. Ind. (1906), 25, 996. 



'Coffignier, Bull. Soc. chim. Paris (1908), .(4) 3, 453. 



8 As Worstall has already shown, Manila and certain other copals are probably 

 free from esters. The term Koettstorfer number implies no knowledge of the 

 chemical structure of the resins and is here preferred to either saponification or 

 acid number. 



