26 JOURNAL OF THE 



ranee of what really constitutes the difference between the pale 

 Rosin and the lower grades. I mean the chemical difference. 

 Chemically, Turpentine is an oleo-resinous juice, consisting of 

 resin and essential oil. The oil, or spirits, varying in amount 

 from 15 — 30 per cent., consists, according to Fliickiger and 

 Hanbury (Pharmacographia, 1879, p. 006), "for the greater 

 part of various hydrocarbons, corresponding to the formula 

 C^oH^g," while Rosin, or colophony, as they term it, may be 

 regarded as composed largely of the anhydride of abietic acid, 

 and has the formula C44Hg204 {id. p. 607). They do not 

 state what Rosin it is that may be so regarded, but w^e will sup- 

 pose that it is the best, or the clear, transparent, nearly colorless 

 Rosin, say the W. W. As you will observe from these speci- 

 mens of the various grades, there is a most marked difference 

 between the W. W. and '' E." or " D." Rosin. The fact I wish to 

 impress upon you is, that we do not know what causes this great 

 difference in color, whether it is due to oxidation, hydration, 

 incipient decomposition, either or collectively. The authors 

 above quoted (p. 607) go on to say that the living tree contains 

 only the abietic acid anhydride; that on exposure to the air 

 the Turpentine loses oil (or "spirits''), takes up water and 

 solidifies as the crystalline acid of formula C44Hg405. The 

 presence of the oil (or spirits) in the turpentine determines the 

 assumption of this molecule of water which changes the amor- 

 ])hous abietic acid anhydride into the crystalline abietic acid. 

 As before reaiarked. Turpentine is a mixture of "spirits'' and 

 Resin. But the "spirits" itself can and does undergo resinifi- 

 cation, which is, |)erhaps, an oxidation, as formic acid is pro- 

 duced. But the resinification of "spirits" does not produce 

 resin, which, as yet, has been shown to be identical with any 

 natural resin. Therefore, we cannot say that resins are oxidized 

 "spirits." A vast amount of chemical work must be done before 

 one can say what is the chemical diU'erence between the grades 

 of Rosin. And yet, if the question of the conversion of the 

 lower into the higher grades is ever settled on a firm basis, it 

 will be settled by the practical chemist. Quo dljjiciUus, hoc 

 prcedare ! 



