Acetic acid is met with among the products from the distillation of wood, and is combined with steam, tar, and gases, such as the oxyde of carbon, hydrogen, and carbonic acid. If, in collecting the acetic acid, the smoke that eontains it is conducted into refrigerators, the steam and the greater part of the tar are con-uensed at the same time, the consequence is, that the vinegar thus obtained is diluted with a large quantity of water and mixed with im purities. For most purposes this acid requires to be purified and concentrated ; the following process, which is taken from the " Genie In-dustriel," is a French invention, and consists in exposing to the vapors of acetic acid during the carbonization, a substance that has an exclusive affinity for it, and which consequently concentrates it. The substances that corinply witH this con4iH. $amp; tit!fi bsses whose acetates are not decomposable at the temperature employed, namely, potassium, soda, bary-tes, lime, magnesium, amp;c, and the carbonates of these bases or of any other salt whose acid can be displaced by vinegar. Of these bodies, preference should be given according to localities,-to lime or the carbonates of lime, magnesium, and soda, the former on account of their cheapness, the latter because it would give directly the acetate of soda a product that is at least employed for the complete purifying of the vinegar. This process is applicable to any method of carbonizing. There are but few places in our country where wood vinegar is made; we know of only one, (Berkshire. Mass.,) there may be others, however. It is used as pyroligneous acid, and employed for the red and black liquids for calico print and cotton dyeworks; the black liquor derives its name from the iron in it, which gives it the said color, and it is used for printing and dyeing cotton blacks.
This article was originally published with the title "Collecting Vinegar from Wood" in Scientific American 8, 19, 145 (January 1853)