Suberate (C_{8}H_{12}M_{2}O_{4}) is known as the salt of suberic acid having a metal cast,[25] and Suberin or cellulose[26]—is that portion remaining after nitration and is chemically expressed by the formula (C_{6}H_{10}O_{5}). Dr. Robert K. Duncan, Prof. of Industrial Chemistry in the University of Kansas, informs us that this material is the commonest of common things[27] and when dry, forms one third of all the vegetable matter in the world. This mysterious substance is the structural basis of the wood, but with all its prominence and use, we know nothing more about it than that which is expressed in the formula. [25] “Watt’s Dictionary” (“M” signifying metal). [26] “Century Dictionary.” [27] _Review of Reviews_, September, 1906. The presence of this cellulose is only a natural fact, as the greater part of plant life is cellulose; nor is the list of elements that go to make up the solid matter so strange and unaccountable, but the quality that makes it a wonderful growth and so popular above its fellows is its lightness—this is its commendable feature and it is light indeed. Ure puts the specific gravity at .24 and this is concurred in by Brisbane. TEST OF CORKWOOD FOR ASCERTAINING THE POSSIBLE PRESENCE OF AN ESSENTIAL OIL, BY STEAM DISTILLATION Two tests were made on this material to ascertain the presence of an essential oil. The first showed the presence of an oily film, resplendent in colorings, opalescent, variegated and beautiful, but odorless and of such small quantity that it may safely be said “No Oil.” The second proved the same as the first, and although the strong odor of cork or suberic acid was present, no oil appeared. The results of these tests indicate that there is no essential oil in corkwood obtainable by steam distillation. TEST NO. 1 4-4-1913. A copper still, supported on two trunnions, fitted with a dome and goose-neck, which terminated in a tin coil (water cooled), and with a perforated bottom through which the steam passed, was used. This measured two inches in diameter and two inches high, from the perforated plate to the top of the pot, the dome being about one foot higher. Into this still was placed 41 pounds of corkwood, as it comes from the cutters and punchers (scrap pieces), no preliminary washing or preparing being done; this 41 pounds filled the pot or the still. All things made tight, using an asbestos packing, the steam was turned on at 70 pounds and run for one hour. TEST NO. 2 4-15-1913. Same still used as in Test No. 1, thirty pounds of a clean, good grade Granulated Cork, of a fineness to pass a 1/16″ mesh, was put into the still—this half filling same. Steam turned on at 70 pounds and run for one hour. Tests made at A. J. Crombie & Co., Brooklyn, N. Y. * * * * *