1912'] The Naval Stores Industry 125 



utilize a bath of molten rosin for removal of the spirits of tur- 

 pentine from the wood, with subsequent distillation of the vola- 

 tile oil from this bath. Such plants seem to have met with a 

 fair measure of success. 



More recently extraction processes have been developed 

 which employ low boiling petroleum products as the extractive. 

 Such plants recover both the spirits of turpentine and the rosin 

 from the ground wood, and have a great advantage in the pres- 

 ent very high value of rosin. These plants are also utilizing the 

 refuse from the straining of rosin at the distilleries in the woods, 

 a product formerly burned on the waste piles, but now bringing 

 nineteen dollars per ton. This method is adding a considerable 

 amount to the annual output of rosin. 



The most recent development is a plant for destructive dis- 

 tillation of wood in retorts heated by jackets filled with high 

 boiling petroleum fractions. By this means a fire risk is prac- 

 tically completely eliminated and the results indicate that by 

 means of the complete and ready temperature control of the oil 

 jacket larger yields of better products can be obtained. 



ANNUAL PRODUCTION OF NAVAL STORES. 



ISTo subject connected with the naval stores industry admits 

 of so little accuracy of statement as does that of statistics on 

 the total annual production. The most careful estimates are at 

 best only approximations. This is unfortunate, for in the past 

 it has frequently led to speculative manipulations of the market 

 and the temporary establishment of values which had no legiti- 

 mate basis depending on supply and demand. 



The following table of annual production is given therefore, 

 as an approximation only, but it is believed to be a reasonably 

 accurate approximation : 



