196 RICHMOND. 



The samples of resin for the above experiments and for that which 

 was examined in the unfnsed state (see p. 183) were taken from a 

 large piece of mined resin weighing about 2 kilograms, hence any changes 

 in the recorded constants are due to the effect of heat under the con- 

 ditions given above. 



The saponiflable portion, that is, the free, amorphous acids, were united and 

 again heated in the same manner as in the previous fusions to their respective 

 temperatures, namely, 275° and 300°, and held at those temperatures with 

 frequent stirring for one hour each. Both showed an appreciable loss in weight 

 and the consequent formation of neutral resin oil. 



"While resin oil is miscible in all preparations with linseed oil and is 

 considered a good solvent for resin acids, and although it undoubtedly 

 does play some part in holding resin acids in solution in boiled oil, it is 

 not believed that its formation in such relatively small amounts has any 

 important role in the manufacture of oleoresinous varnishes. 



After the second fusion of the united resin acids obtained from experiments 

 2 and 3, the masses were dissolved in alcohol, neutralized with alcoholic potash, 

 and separated into alcohol soluble and insoluble potassium resinates as before. 

 The liberated resin acids behaved in a manner entirely similar to those obtained 

 from the crude resin. They could not be made to crystallize, hence combustions 

 and cryoscopic determinations were not repeated; but their melting points, solu- 

 bilities, and other physical properties showed no appreciable alteration. 



The fused acid gave an acid value of 164 milligrams of KOH, as compared with 

 169 to 170 before fusion. 



Differences in the behavior of the fused and unfused resin acids indica- 

 tive of profound decomposition or depolymerization were not observed. 



It has been shown that the melted resin differs from the raw resin only 

 in the amount and nature of the unsaponifiable portion, and that the resin 

 which enters into varnish manufacture consists essentially of free acids 

 of the same composition as they had when in the original copal. There- 

 fore, it would seem that any real or assumed reason for subjecting the 

 oil and resin to elevated temperatures, both before and after mixing, 

 should be looked for elsewhere. 



THE USE OF MANILA EESIN FOE OLEOEESINOUS VAENISHES WITHOUT PREVIOUS 



FUSION. 



Owing to the loss of weight and the considerable darkening in color 

 which all resins undergo during the melting process, many attempts have 

 been made to render raw copals soluble in linseed oil. 



Livache ls makes turpentine varnishes from unmelted Kauri and Manila copals 

 by first dissolving them in alcohol to which a trace of nitric acid has been added, 

 then adding the turpentine and removing the alcohol by distillation. To make 

 oleoresinous varnishes, the spirit varnishes thus prepared are dissolved in a 

 mixture of linseed oil and the free fatty acids of linseed oil. 



ls Co?npt. rend. Acad. sci. (1907), 146, 896. 



