OCCURREXCE OF PODOCARPIC ACID. 



153 



8._N0TE ON THE PHYSICAL CHEMISTRY OF PHOSPHOROUS ACID. 

 By T. H. EASTERFIFLD and H. T. REVELL. 



Abstract. 



Phosphorous and glacial acetic acids are miscible in all pi-opor- 

 tions. The temperature lies at about 7 degrees, and corresponds 

 to a mixture containing 36 per cent, of phosphorous acid. 



The rate of fall of the freezing point of acetic acid due to the 

 addition of phosphorous acid obej^s a straight line law for concentra- 

 tions not exceeding 3 per cent. The mean value for the molecular 

 weight of phosphorous acid deduced from four determinations was 

 82'4, the minimum being 80 and the maximum 85; the value cal- 

 culated for the fonnula H3PO3 = 82'0. 



At concentrations above 6 per cent, the fall in freezing point 

 produced by the successive additions of phosphorous acid is also 

 directly proportional to the amounts of substance added, but the rate 

 of fall is now only one-third as great as was the case at concentrations 

 below 3 per cent. The molecular weight of the acid is thus three times 

 as great in concentrated as in dilute solution. The mean value of the 

 molecular weight of phosphorous acid at concentrations between 6 and 

 20 per cent, was found to be 244, tlie maximum value obseiwed being 

 259, the minimum 225. 



The formula (H3P03)3 requires a molecular weight of 246. 



Phosphorous acid is readily soluble in moist ether, but practically 

 insoluble in ether which has been dried over sodium, and no suitable 

 solvent has been found for determining the molecular weight of 

 phosphorous acid by Ebbulioscopic methods. 



9.— THE OCCURRENCE OF PODOCARPIC ACID IX NEW ZEALAND 

 RED AND WHITE PINE. 



By MISS A. I. SLOWEY, M.A. (Wellington, N.Z.). 



Abstract. 



Podocarpic acid C17H22O3 is the chief constituent of the heart- 

 resin of I'odocarpus cupressina, var. imhricata, a native of Java ; it 

 was isolated by Oudemans (Annalen, 170, 213), in 1870, but does not 

 appear to have been observed in any other tree. Of the New Zealand 

 timber trees the Red Pine or Rimu (~Dacriclium cupressinum), the 

 White Pine, or Kahikatea (Podocarpus dacridioides), and the Matai 

 (Podocarpus spicata) are known to contain heart-resin. 



A preliminar}'' note on rimu resin has already been published by 

 Eastei-field and Astor (Chemical Society Proceedings, 1903, 190). 

 These authors found that the portion of the resin soluble in alcohol 

 consisted of a crj^stalline acid which they called rimuic acid, and to 

 which they ascribed the formula C18H24O3, the percentage composition 

 of which is nearly identical with that of podocarpic acid. 



The present investigation was undertaken at the suggestion of 

 the last-named authors, with the object of ascertaining whether rimuic 

 and podocarpic acids are identical, whether White Pine and Matai 

 resins also contain the same acids, and whether the formulae ascribed 



