The result of this graduated distillation, at a high temperature, is that we have obtained over 90 per cent. of the whole crude product in a series of oils, having valuable properties, although not all equally fitted for illumination and lubrication.
A second distillation of a portion of the product which came over in the later stages of the process (a portion distilled at about 650° F., and having a high colour), gave us a thin oil of density about .750, of light yellow colour and faint odour.
It is safe to add that, by the original distillation, about 50 per cent. of the crude oil is obtained in a state fit for use as an illuminator without further preparation than simple clarification by boiling a short time with water.
DISTILLATION BY HIGH STEAM
Bearing in mind that by aid of high steam, at an elevated temperature, many distillations in the arts are affected which cannot be so well accomplished by dry heat, I thought to apply this method in case of the present research. Instances of this mode of distillation are in the new process for Stearine candles, and in the preparation of rosin oil. I accordingly arranged my retort in such a manner that I could admit a jet of high steam into the boiler, and almost at the bottom of the contained petroleum. I was, however, unable to command a jet of steam above 275° to 290° F., and although this produced abundant distillation, it did not effect a separation of the several products, and the fluid distilled had much the same appearance as the petroleum itself, thick and turbid. As this trial was made late in the investigation, I have been unable to give it a satisfactory issue, chiefly for want of steam of a proper temperature. But I suggest, for the consideration of the company, the propriety of availing themselves of the experience already existing on this subject, and particularly among those who are concerned in the distillation of rosin oil—a product having many analogies with petroleum in respect to its manufacture.
USE OF THE NAPHTHA FOR ILLUMINATION
Many fruitless experiments have been made in the course of this investigation which it is needless to recount. I will, therefore, only state those results which are of value.
1. I have found that the only lamp in which this oil can be successfully burned is the camphene lamp, or one having a button to form the flame, and an external cone to direct the current of air, as is now usual in all lamps designed to burn either camphene, rosin oil, sylvic oil, or any other similar product.
2. As the distilled products of petroleum are nearly or quite insoluble in alcohol, burning fluid (i. e., a solution of the oil in alcohol) cannot be manufactured from it.
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