121 



quality contains at most 2,5 °/ of "normal impurities" and not more 

 acids than correspond to degree of acidity of 1,0. 2. Second class 

 oil: maximum of impurities 3 °/ , ditto of acidity 3,0. 3. Third class 

 oil: respectively 5% and 5,0. 4. Oils which show figures exceeding 

 5°/ and 5,0 respectively are to be regarded as adulterated. 



Other researches by the same author, of which only a synopsis 

 of results is given, had for their object the better separation of crude 

 turpentine into two layers: water and pure turpentine; the boiling 

 point determinations of various mixtures of water, turpentine oil, and 

 colophony; the determination of the composition of an oil-and- water 

 mixture passing over at definite temperatures, and, finally, controlling 

 tests for these conditions in works-practice, the object of the whole 

 being to prepare a heat-chart for turpentine distillation. After referring 

 to his previous work on separation- curves of mixtures of water, alcohol 

 and oil of turpentine, Vezes reports on experiments in the preparation 

 of rosin acids from colophony. To the latter, however, we will not 

 refer in detail, as they are outside our sphere of interest. 



While in most of the methods which have been proposed for the 

 testing of oil of turpentine chemical processess are employed in order 

 to ascertain the normal character of the oil, Geer 1 ) proposes to esti- 

 mate the purity of oil of turpentine by determining the principal physical 

 constants of the oil after fractionating by water-distillation, with the 

 assistance of a suitable distilling head, or of the fractions themselves. 

 The reason why Geer uses water-distillation of the oil is to avoid super- 

 heating, which cannot be avoided in the case of dry distillation owing 

 to the height of the condenser. This superheating would of course in- 

 fluence more or less the constants of the oil-fractions. The exami- 

 nation is carried on as follows: Exactly 500 g. of the sample are placed 

 in a boiling flask. The still head, which is over one yard in height and 

 in which 5 small funnels with horse-shoe shaped tubes have been placed 

 in a suitable manner, is provided below the exit-tube with a thermo- 

 meter divided into Vio ' as well as with a dripping-funnel from which 

 during the process one drop of water per second runs into the still- 

 head. A gentle steam -jet from a simple water -boiler provided with 

 a safety tube and cock is introduced into the oil, so that two drops 

 of the distillate pass over every second. The distillate is collected in 

 separate fractions (usually 10 to 15), the size of which depends 

 upon the rise in temperature, and therefore varies in different oils. 

 The collection takes place in weighed measuring-glasses and by weigh- 

 ing the gross contents and deducting the weight of the water which 



1 ) The analysis of Turpentine by fractional distillation with steam. U. S. Dept. 

 Agriculture, Forest Service, Circular 152. Washington 1908. Chem. Ztg.33(i9Q9), 859. 



