— 128 — 



in the action of the two stills, but it is said that no definite judgment can 

 yet be formed. So far as the evaluation of an oil-fraction in respect of 

 its value as good, low-boiling wood turpentine is concerned, neither the 

 often varying temperature of the steam which passes over, nor the specific 

 gravity of the oil-particles is conclusive, but rather, according to practical 

 experience, the respective proportions of oil and water in each fraction 

 that distils over. The higher the proportion of oil, the more closely the 

 properties of the oil approximate those of a good wood turpentine. When 

 the total-distillate contains 55% oil or more, the proportion of good oil 

 boiling below 170° is 90%; when the total proportion of oil ranges from 

 55 to 30%, renewed steam-distillation is needed in order again to obtain 

 a light portion containing 55% of good oil (as before). Finally when the 

 oil-content of the total distillate falls below 30%, it consists entirely of 

 high-boiling oils, which it is unneccessary to try to work up for oils with 

 b. p. below 170°. 



With a view of deciding the important question to what extent the 

 various wood turpentines could be used in the manufacture of paints 

 and varnishes side by side with gum spirits, several varnishes were pre- 

 pared with four samples of commercial oils, consisting of one sample each 

 of guaranteed pure oil from gum of a steam-distilled wood turpentine, 

 and two wood turpentines prepared by the destructive process and sub- 

 sequently washed with soda and steam-distilled. In connection with these 

 experiments it is expressly stated that, apart from one of the two samples 

 last-mentioned, the wood oils contained large proportions of heavy oil, 

 from which they derived a pronounced odour, and which caused the var- 

 nishes prepared with them to dry more slowly than usual. It is evident 

 that varnishes prepared with oils of this description must give less satis- 

 factory results than when a well-rectified oil had been used. From each 

 of the four samples two kinds of varnishes were prepared, a coach 

 finishing varnish and a piano varnish, with a view of testing their 

 qualities under different atmospheric influences. We* are unable to 

 quote here the very detailed reproduction of the reports of the numerous 

 firms which instituted these tests; partly preparing the varnishes them- 

 selves, and partly using them only. The disagreeable odour and the irritant 

 action of the wood turpentine are generally commented upon; on the 

 usefulness of the varnishes themselves the opinions differ. On the other 

 hand the producers of wood turpentine of course claim that their pro- 

 ductions are entirely suitable for the manufacture of paints, varnishes, ^ 



We are now able to complete, on the authority of an American report, 

 the particulars given in our last Report (p. 92) concerning the output of 

 the various products of the American wood-distilling plants 1 ). From this 



i 



x ) Oil, Paint and Drug Reporter 80 (1911), Na. 26, p. 9. 



