BUREAU OF CHEMISTRY. 265 



and scoured wool us regards moisture content under various condi- 

 tions of temperature and humidity. A paper on "Wool-scouring 

 wastes for fertilizer purposes " was published during the year. Both 

 the direct and indirect results of work of this character are to in- 

 crease the value of a raw agricultural product after it has been pro- 

 duced, increasing the profit to the producer and lowering the cost to 

 the consumer. 



NAVAL STORES INVESTIGATIONS. 



Turpentine and rosin are among the world's important farm and 

 forest crops, and of the total this country produces approximately 70 

 per cent. Several millions of dollars can be saved annually to the 

 producer through research and demonstration work. The crop is 

 peculiar in that it is grown and gathered in the eight southernmost 

 States, but practically all of it is used north of the Ohio and east of 

 the Mississippi rivers or is exported. The producers have not the 

 facilities or the means of solving the many problems that arise. 



As a result of an investigation during the year on methods for 

 producing rosin esters for varnish manufacture, discovery was made 

 of the fact that when zinc or a zinc compound is used as catalyst, 

 rosin and glycerin can be made to combine more easil}^ and more 

 rapidly than was heretofore possible, yielding a product of low acid 

 number and light color. A public-i:-ervice patent covering this 

 process Avas obtained. Several varnish manufacturers have coop- 

 erated by preparing batches of varnish from samples of rosin ester 

 made in this laboratory and subjecting these varnishes to wear and 

 weathering tests, which are still in progress. Small quantities of 

 complex compounds made from turpentine and sulphur and from 

 turpentine and oxalic acid were prepared to determine whether they 

 could be used in connection with the work on waterproofing of fabrics. 



Investigations on the chemical properties of turpentine and rosin 

 have been continued. To determine whether any differences other 

 than color exist between the various grades and varieties of rosin, 

 analyses were made of authentic samples originating at various 

 points in the producing sections. It was found that there is a dif- 

 ference, although not a very marked one, between the chemical prop- 

 erties or constants of light-colored rosins and those of dark-colored 

 rosins. 



Incidental to this investigation it was found that the constants of 

 rosin change appreciably and rapidly on standing after being pow- 

 dered. A sample of rosin produced about 50 years ago was found 

 to have an abnormal tendency to crA'stallize, crystalline rosin acids 

 being readily obtained from solutions in alcohol. A number of au- 

 thentic samples of wood rosin examined differed from gum rosin, 

 not only in having a lower melting point but also in having lower 

 saponification, acid, and iodine numbers, and containing more un- 

 ^-aponifiable matter. Several samples of foreign rosins were also ex- 

 amined. Examination of old turpentine samples disclosed the fact 

 that they had developed marked acidity and had a decided solvent 

 effect on iron, zinc, and copper. Several samples of so-called '• re- 

 covered turpentine " were found to contain oxidized and chlorinated 

 bodies, in addition to the usual turpentine constituents, and were 

 identified as a by-product from the manufacture of synthetic 

 camphor. 



