Repository: UIHistories Project: Board of Trustees Minutes - 1880 [PAGE 109]

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107 of air, and that the amount of oils of a low boiling point in kerosene is comparatively small, it will appear that this method is utterly worthless. The vapors given off at a low temperature are disseminated through a large volume of air, and pass off unrecognized, and the oil begins to flash only when the temperature is sufficiently high to vaporize those oils which have a boiling point high enough to be considered safe. In a lamp or other closed vessel, the vapor from those hydrocarbons having a low boiling point accumulates in the space above the oil, and produces, with the air, an explosive mixture. The law in our State requires the oil to be tested with some approved apparatus, as "Tagliabue's Tester." In the use of apparatus of this kind, there is still one fallacy, although not so great as that mentioned above. The apparatus during the operation of testing the kerosene is in a state of rest. But after the boiling point of a dangerous hydrocarbon is reached, it takes some time for the vapor to disengage itself from the remainder of the kerosene and mix with the air contained in the empty space of the tester, so as to produce the flash. In the meantime, however, the heat is continually applied, and the temperature of the kerosene is gradually raised. Hence, the flashing point is invariably given a number of degrees too high. The true flashing point of kerosene is the lowest temperature at which it will flash after it has been shaken up with a quantity of air, equal in volume to about one-half or onethird of that of the kerosene employed, as first shown by Prof. Meyer, of Zurich. To make the test in this manner with ordinary apparatus, however, requires some skill, and much time and labor. To meet this difficulty, I have designed and used a tester, by which the test may be made as rapidly and easily as in the usual manner. It consists of three cylinders of common sheet tin, the largest of which is about eight inches high and four inches in diameter, and is entirely closed, with the exception of a circular opening in the top of about one inch and a half in diameter. Into this opening, the next cylinder, which is open at the top, and is two inches shorter than the large one, exactly fits. The large cylinder is nearly filled with water, and the second cylinder, which is filled to within an inch or two of the top, is inserted into it. The whole is then covered with a tin disc, having a hole in the center, through which the stem of a thermometer can readily pass. To the bulb of the thermometer the third cylinder is attached, by means of a perforated cork. This cylinder is about one and a half inches in length, and fits closely into the second cylinder. It is closed at one end, with the exception of a hole in the center for attaching it to the thermometer, and a series of small holes for the escape of air and gas. When properly attached to the thermometer, it is inserted into the second cylinder, with its open end downward. The disc mentioned above is then placed over the w7hole, the stem of the thermometer projecting out through the central opening. Thus charged, the whole is placed over a small alcohol lamp, or Bunsen's burner, the heat being so regulated that the temperature of the kerosene does not rise more than one or two degrees a minute. While the heat is thus applied, the short cylinder is moved up and down, by which means the air and kerosene are brought into contact and the latter