345 



sufficient amount of a lo per cent, aqueous solution of soda was added to 

 form a dense precipitate, and it was then heated to dissolve the precipitated 

 salt. On cooling, a considerable amount of the soda salt separated, but the 

 separation was not quite complete because, on the addition of solid caustic 

 soda a further precipitate was obtained, but this being dark coloured 

 it was discarded. The soda salt was dissolved in water, acidified, and the solution 

 boiled, the separated substance melting in the hot water to a yellow brittle lump 

 of resin. The above process was repeated three times, and the resin was then 

 heated on the water bath till quite dry. Although melting at a low temperature 

 it was quite brittle, and when powdered was of a light yellowish colour. 



This freshly prepared acid melted at 84°-85° C, and the melting point 

 was the same after one month, but after six months the melting point had 

 increased to 90°-gi° C. Although acting similarly in some respects, yet, it is a 

 different acid from the corresponding one in Agathis robiista. It was soluble in 

 the cold in 70 per cent, alcohol, but not very readily, and on slow evaporation of 

 the alcoholic solution, no crystalline product was obtained. The acid was dis- 

 solved in chloroform, and acetic anhydride added, when one drop of sulphuric 

 acid changed this solution at once to a deep violet colour, which soon altered to 

 an olive-green tint. 



The acid was Isevo-rotatory, but not very markedly so, and o-8 gram in 

 ID c.c. alcohol in 100 mm. tube rotated the ray o-g° to the left ; the specific rotation 

 was, therefore, [rt]i, — 11-25°. 



0-2408 gram acid dissolved in alcohol, required 8 c.c. decinormal NaOH 

 to neutralise it ; 40 grams NaOH would, therefore, neutralise 301 grams acid. 



0-1664 gram in alcohol required 5-5 c.c. ni NaOH, so that 40 grams NaOH 

 would neutralise 302 grams acid. 



0-1559 gram required 5-1 c.c. f„ NaOH, or 40 grams NaOH would neutralise 

 305 grams acid. 



Analysis gave the following :— 



0-1476 gram gave 0-4285 gram CO.,, and 0-1292 gram HjO. 



C. = 79*2; H. = 9-73 per cent. 

 CooHgoOo requires 79-4 per cent. C, and 10 per cent. H. 



The silver salt gave the following result : — 



0-2184 gram silver salt gave 0-0574 gram silver = 26-28 per cent. Ag. 

 C.2nH.,.iAgO., contains 26-4 per cent, silver. 



From the molecular determinations, and the result of analysis, the formula 

 QoH^dOi is indicated for the acid of low-melting point in the resin of Arancaria 

 Cunninghamii . 



