SCIENCE AND INDUSTRY. 
The yields of picric acid from the different species vary very much. 
The following figures are given by Mr. H. G. Smith -— 
New South Wales yellow resin gave 48 per cent., 48 per cent., 
and 36 per cent. picric. if 
Kangaroo Island red resin gave 46 per cent., 44 per cent., and 
44 per cent. picric. - 
Western Australian red resin gave 23 per cent. picric. 
Queensland red resin gave 24 per cent. picric. 
These are percentages for the unpurified acid. It has been found 
that the purification of picric acid made from Grass Tree resin is a 
laborious matter, it being troublesome to remove all traces of colouring 
matter, and to obtain a solid with constant melting point. It is not at 
all easy to compare the cost of production of picric acid from X. resin 
and from phenol, as so much depends not only on the yield obtainable, 
but also on the consumption of nitric acid, and on the time and labour 
involved in the purification of the product. 
Since the outbreak of the war, the possibility of utilizing these 
resins as a source of picric acid was independently investigated by the 
Imperial Institute, a sub-committee of the New South Wales Munitions 
Committee, and a sub-committee of the Federal Munitions Committee. 
The New South Wales Committee concluded that, “ Taking everything 
into consideration, it would be more economical to manufacture picrie 
acid from the phenol recoverable from the available supplies of coal 
tar than to manufacture it from Grass Tree resin.”. 
When 12 or 13 lbs. of nitric acid are used to 1 lb. of resin, 50 per 
cent. is the maximum of picric acid obtained, so that it requires 24 lbs. 
of nitric to make 1 lb. of picric:from Grass Tree resin. ‘To make picric 
from phenol, the rate is only 4 lbs. to 1, 2.e., one-sixth of the amount 
of nitric is required. The amount of phenol obtainable from the coal] 
tar produced annually in New South Wales may be calculated. Seven 
million gallons of coal tar made annually yielding .5 per cent. phenol, 
would produce 350,000 Ibs. phenol, and this would provide 660,000 lbs. 
picric acid, which is now going to waste. With nitric acid at £24 a 
ton, the following rough estimate of cost of manufacture of 1 lb. of 
picric acid from resin and- phenol respectively is calculated :— 
With Grass Tree Resin— 
WNitrichacidenay ki | Wuscr ey uh wheat 
Yellow resin e Be Aa AES ea 
Purifying resin .. iwi Lofiesn pUSeEodte 
' Manufacturing, &c. ree oe BBO ADL 
BS TH, 
With Phenol—. ris see he Rone 
Nitric: acids; i: .<° wine! Teh ons 9408100. 
eRhenol) Wie shook, oe sore l Leetitee, JeONe0e Od? 
~Sniphnrcacids 2. tis Geerasy soci th Ose 2dh- 
Manufacture» ete Pees 4 ee Tyrer 6d) Riba 
| . adh 4s, 6d 
284 
