FOREST UTILIZATION 115 



(c) After closing the upper funnel, apply heat very 



gradually. Within 24 hours turpentine begins 

 to escape through the top pipe which leads 

 through a worm into a condenser. When the 

 gases appear dense and thick, the top pipe is 

 closed and the gases (now largely containing 

 pyroligneous acid) are forced through the bot- 

 tom pipe to be condensed in another con- 

 denser. Light (at a later stage dark) tar is let 

 out through this same pipe. The fires are 

 checked when the tar begins to flow freely. 



(d) The process takes, for heating, 3 days; for cool- 



ing, 8 days. Charcoal is left in the still room. 

 Proper regulation of temperature is most essen- 

 tial. 



(e) One cord of pine kindling yields about 25 gal- 



lons of tar, i to i J /2 gallons of machine oil, y>, 

 to i gallon of turpentine, some pyroligneous 

 acid and Yz cord of charcoal. 

 III. Uses of naval stores: 



(a) Spirits of turpentine are used for colors, paints, 



varnishes, asphalt laying, solvent for rubber. 



(b) Colophany is used for glue in paper manufacture, 



varnishes, soap making, soldering, manufacture 

 of sealing wax. 



(c) Wood tar made of conifers is lighter than water 



(owing to spirits of turpentine therein con- 

 tained) ; made of broadleafed is heavier than 

 water. It contains tolnol, xylol, cumol, naph- 

 talin, paraffin, phenol, kreosol, pyrogalol and 

 many other carbohydrates. 



Caustic soda causes the solution of the aromatic 

 alcohols contained in wood tar. From this solu- 

 tion true creosote is derived. 



Dry distillation of wood tar yields : 



1. Light wood oil; 



2. Heavy wood oil ; 



3. Shoemaker's pitch, a residue. 



D. Conifers other than pines are used only to a limited degree in the 

 manufacture of naval stores. 



(a) The larch yields the so-called Venetian turpentine, 



which is obtained by boring (with ij^ inch 

 auger) a deep hole into the heart of the tree. 

 The hole is closed by a plug. After a year the 

 turpentine, entirely filling the hole, is extracted. 



(b) Spruce was tapped for turpentine on a large scale 



in the old country before the orchards of the 

 South were developed. Only scrape is obtained 



