Feb.,
1913
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E J I I S T R I'
commercial work where the extractions must be done in a short time and to more accurate scientific work where the substance is extracted for a longer time. A set of twenty of these extractors has been in use in this laboratory for about six months and has proved entirely satisfactory with a variety of substances. FEED A N D MICROCHEMICALLABORATORY O F AGRICULTURE NORTHCAROLINA DEPARTMENT RALEIGH
1.51
below. The apparatus shown has two decks thoroughly insulated and with a two-inch air space between decks as a safeguard to overheating. The heating is furnished by 16 c. p. incandescent bulbs and a spun
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a 3 c
A REFLUX CONDENSER By S. W. WILRY Received October 25, 1912
The piece of apparatus discussed in this paper was designed because of the small space occupied by it and the degree of efficiency obtained by its use in comparison with other types now on the market. This condenser as shown has been used by Wiley & Company's laboratory and has given great satisfaction. We have found it indispensable for extraction with ether or other solvents or for any purpose where a refluxcondenser can be brought into use. The cuts show clearly the construction of the various parts and, from a close inspection of the cuts, a n adequate idea of the large condensing surface that can be obtained in comparison with the size of the water jacket. The condensing tubes are of block-tin tubing and on entering the water jacket are connected to bell-shaped condensers of spun copper. On entering the bell which is composed of two sections, the uncondensed ether passes through perforations and is condensed on the upper surface of the bell. The condensing surface of this arrangement is over 1 2 0 square inches in comparison t o the straight tube usually used, two feet being the length that is ordinarily used with a n internal diameter of 3 / / , inch which would have a condensing surface of about 2 5 square inches. The water inlet is so arranged t h a t the water bubbles up and surrounds every portion of the condenser, and by this scheme we have the condensing surface continually exposed to fresh, cold water thus insuring continual condensing of the solvent with a minimum loss. To this condenser any form of extraction apparatus may be connected and in this laboratory a special form is used, which is simple in construction and a t the same time efficient. For heating the solvent we use the scheme shown
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cup, insulated on the outside to prevent radiation, surrounds the bulb and forms a rest for the extraction bulb. ANALYTICAL LABORATORIES WILEY& Co. BALTIMORE
ADDRESSES
TAR DISTILLATION IN THE UNITED STATES-GENERAL DEVELOPMENT AND RECENT PROGRESS' B y R. P. PERRY INTRODUCTION
One feature of the general conservation movement which has attracted fnuch attention in recent years is the estimated use and available supply of coal. For years our household and factory fires have been burning cheerfully-although in many cases rather smokily-and we have had a n optimistic feeling that our Paper presented a t the Eighth International Congress of Applied Chemistry, New York. September, 1912.
II
coal mines were inexhaustible. Even now fuel is so plentiful and comparatively cheap in many parts of the country that a large portion of the public forgets that there may be a cold tomorrow. If we travel by night through the Connellsville section we see the glare from thousands of beehive ovens light up the sky and throw picturesque shadows on the hills, but if we study the careful and interesting reports of the United States Geological Survey, we may well be amazed a t the apparently reckless annual waste of millions of dollars worth of by-products-gas, ammonia and tar-from these ovens, when converting bituminous coal into coke for the great iron and steel industry. At the same time,
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