Testing the Quality of Turpentine

Before giving details as to the sources and characteristics of the best terpenes, it may be useful to mention that commercial samples of spirit of turpentine may be tested and compared by means of a very simple experiment. Obtain the required number of small flat-bottomed, conical glass flasks with wide mouths, one flask for each sample; these flasks are known as Erlenmeyer's. Into the flasks pour enough of the several samples to cover the bottom to the depth of one-eighth of an inch; label each flask to correspond with the sample, and lightly close each mouth with a plug of carded cotton - the date of the experiment should be added on the label. Shake each flask so as to cause a number of bubbles to be formed in the liquid; the more rapidly these bubbles break, the better is the sample. Repeat the experiment of shaking the samples at short intervals for a few weeks - notable changes in the viscosity of the oils will be observed sooner or later. Any sample which after one month remains clear, and in which the bubbles formed on agitation break almost as quickly as at first, may be accepted as of good quality.

Another test for discriminating between the samples, so far as their state at the time of the experiment is concerned, is the very simple one of placing one drop of each oil upon a sheet of writing-paper, and gently warming the translucent stain it forms; with a good oil the mark completely disappears.