REPORT OF THE FARMERS' CLUB. 51 



3. Insert the thermometer in its ring and secure the cover to the 

 pins outside. (See the second view.) 



4. Half fill the small lamp with alcohol, trim it so as to produce 

 as small a flame as possible, light it and put it in its place below 

 the water bath. 



5. Allow the mercury to rise to within ten or fifteen degrees of 

 the temperature at which the oil is to be tried, or at which it is 

 expected to vaporize ; then remove the lamp, and open the two 

 valves which have previously closed the small openings d d in the 

 cover of the instrument, so as to permit the entrance of atmospheric 

 air, and its mixture with the vapor arising from the oil. 



6. Then insert a lighted taper through the orifice c in the cylinder 

 and a faint puff or small explosion of vapor will occur if the lowest 

 explosive temperature of the oil has been reached. As soon as this 

 puff is seen, the thermometer must be carefully examined, and the 

 mercury will indicate the precise degree at which the oil produces 

 an explosive mixture with atmospheric air. 



1. If the taper does not cause a "pufi"," replace the lamp within 

 the stand, and let it remain there a few seconds, until the mercury 

 first begins to rise, then withdraw the lamp, and again apply the 

 taper to the orifice c; but if still no "pufi"" occurs, repeat the 

 operations described in this paragraph until it does so. 



8. When it is desired to ascertain the temperature of the coal 

 oil at the point of its ignition on the approach of a flame, first take 

 out the lamp, turn the sliding cover till the surface of the oil is 

 exposed to the air (see first view ;) then replace the lamp beneath 

 the water bath and watch the thermometer until the mercury has 

 reached the degree shown by the first experiment. Remove the 

 alcohol lamp, then repeatedly apply a small flame at the level of 

 the edge of the oil vessel, and as soon as the oil begins to burn the 

 thermometer will truthfully exhibit the exact temperature at which 

 the oil becomes inflammable. In making this experiment, vapor 

 will occasionally collect and escape over some single spot in the 

 oil; it is here wdiere the flame should be applied, and it should 

 never be held longer over one spot than a few seconds. The alco- 

 hol lamp may be replaced if necessary, as in the first experiment, 

 as in direction seven. 



9. After the alcohol lamp is removed, the thermometer rising 

 one degree per minute, will be best suited for uniform observation. 



N. B. Care must be taken to follow the exact measures of oil 

 mentioned in direction two — neither more nor less. 



