ELISHA MITCHELL SCIENTIFIC SOCIETY. 29 



denser. Tliis condenser alongside the fnrna(;e is a wooden vat 

 12 feet high and 10 feet in diameter, connected with the water- 

 works, so as to secnre a continuous flow of water, and contains 

 a copper worm about 40 feet long, narrowing gradually to IJ- 

 inch tube. On issuing from condenser this worm enlarges into 

 a goose neck, or trap, in which the uncondensed gases and the 

 liquid are separated. The gases are conveyed to another con- 

 denser and to the reservoir and are used for heating purposes. 

 .The liquid falls into a wooden vat of convenient shape and hold- 

 ing about 900 gallons, and connected by siphon and pump with 

 reservoirs in the creosoting house. Each retort is a complete still, 

 and a battery occupies a ground space of 26 feet by 26 feet. 

 A retort, with ordinarv care, should last 15 vears. The workinir 

 is simple. Good, resinous, fatty pine wood as having the high- 

 est content in oil is selected, and 4^ cords carefully laid in the 

 retort, the ends sealed, and firing begun. The heat is gradually 

 raised, driving off water, light gases and oils, until between 400° 

 F. and 760° F. the heavy and most valuable oils distill. These 

 are carefully condensed, not allowing the water in the vat to get 

 more than lukewarm. The heating is kept up continuously for 26 

 hours, consuming about one cord of wood per battery, after which 

 time the fires are removed and the retorts cooled as rapidly as 

 possible. The charcoal, amounting to about 33 per cent, of 

 charge, is raked out and meets with ready sale. The entire opera- 

 tion requires between 30 and 36 hours, with a yield of about 70 

 gallons creosote oil and 85 to 90 gallons pyroligneous acid waste 

 per cord. The uncondensed gases l)eing separated from liquid 

 in the goose neck, are conveyed through another small condenser 

 (recently added), wherein small quantities of oils are further 

 (condensed, passing over lime (unslacked), according to Stanley, 

 and into reservoir, from which it is drawn and used for heating the 

 retort. The distillate, upon standing (usually until the retort is 

 charged again), separates into two liquids known as pyroligneous 

 acid waste, consisting of water, pyroligneous acid, acetone, a 

 small proportion of lightest oils and about 1 per cent, wood 

 alcohol, and "creosote oils,'' consisting of 5 per cent, tar acids, 



