COAL-TAR AND WATER-GAS TAR CREOSOTES. 21 
In this country there is little demand for either carbolic oil or 
anthracene oil. In general, therefore, these fractions are included 
in the creosote oil, ahd for the most part only three fractions are 
taken, namely, light oil, up to 200° or 210° C; creosote oil, up to 
pitch; and pitch. The distillation is not carried so far as it is in 
Europe, but is run only to soft pitch. It is, therefore, expected that 
American oils will, in general, be somewhat lighter in specific gravity 
than the European oils, because the carbolic oils are usually included, 
and the distillation is not carried to so high a temperature. 
It sometimes happens, however, when the demand for pitch is not 
very great, or when a special oil is desired, that the tar is distilled 
until only coke remains in the still. The coke, which is a very pure 
carbon, finds a sale for purposes similar to those for which retort 
carbon is used. The creosote, in consequence of the high temperature 
used in this distillation, is very high boiling and has a high specific 
gravity. There are at least two plants in this country which make 
special oils in this way. 
Creosote oil, as it appears on the market, is not always a product 
obtained by the straight distillation of tar. It is frequently mixed 
with other products of coal tar, which are not of any value in other 
industries. For instance, the oil obtained by pressing the anthracene 
cake frequently finds its way to the creosote-oil tank, as does also the 
phenanthrene which results from the purification of the anthracene 
cake. The high-boiling oils known as carbolineums are, essentially 
expressed, u anthracene oils." In this country, tar is sometimes 
added to light creosote oils to raise their gravity. This tar may be 
either water-gas tar or low-carbon coal tar. The light creosote oils 
are sometimes redistilled, to remove part of the light oil and naph- 
thalene and thus produce an oil that will fulfill specifications otherwise 
not met by the total distillate. 
The amount of material classed under u creosote" that was pro- 
duced, imported, and used in this country is shown by Table 7, 
covering the last nine years. These figures include not only straight 
distilled products of coal tar, but, in all probability, water-gas-tar 
creosotes, mixtures of water-gas-tar creosotes and coal-tar creosotes, 
and mixtures of either or both with coal tar, either refined, filtered, 
or crude, as well as mixtures of either or both with water-gas tar. 
No estimate of the amount of these mixtures can be made. 
