Trans. N. V. Ac. Set. 142 Mar. 13, 



introduced from time to time, until the plug was driven out by the force 

 of the explosion of the mixture of vapors and air within. 



At first sight this appears to be the acme of oil-toilers; but, alas, it 

 has several important faults. It is not a matter of indifference how the 

 plug is placed in the tube. If it is too tight, it will not be ejected by 

 the explosion, and the flame will force itself out at the side valve. It is 

 also important that the instant of right admixture of vapors and air 

 should be the instant that the flame is introduced. For if the air con- 

 tains more vapors than will form an explosive mixture, simple combus- 

 tion at the valve, and not explosion, is the result. By introducing the 

 electric spark as a means of ignition, the difficulty of admixture maybe 

 overcome ; but the force necessary to eject the plug must always be a 

 difficulty. 



In this paper I have not been able to discuss all the various appa- 

 ratus used for testing kerosene oil ; but I have taken some of those most 

 used, and that are types of others. 



Yet one other apparatus remains to be noticed, and this is the " elec- 

 tric closed tester," devised by Mr. Pease, of Buffalo. In this appa- 

 ratus we have the usual oil-cup and water-bath. But the oil-cup has a 

 cover, and an overflow tube to insure the level of the oil remaining the 

 same during the process of heating ; since the heating causes expansion 

 of the oil and thus raises the level. Into the cover of this tester are fitted 

 two wires, between which a spark from an induction-coil may be passed. 

 The usual outfit of thermometers completes the apparatus. 



This apparatus is very nicely made, and the overflow-tube is an im- 

 portant device, especially with the heavier oils. But, in working with 

 this tester, I was surprised to obtain results very little better than with 

 an open tester. This is due to the fact that the spark-wires are in the 

 centre of an opening in the cover, and that this opening is so large that 

 the vapors escape around the sides without being ignited. To prove 

 this, I covered the opening with a small piece of glass, and obtained a 

 flash at a much lower temperature, because the vapors could not escape. 



For the sake of comparison, I have tabulated the results obtained 

 with the various apparatus, and the quantities of oil used in each. 



Flash. 



Tagliabue's (open) 2 ounces 



Saybolt's (open) 2^ 



Tagliabue's (closed) I 3 



Abel 's (closed ) ' 2% 



Bernstein's (closed) j 1^ 



Wisconsin (closed) 1 5 



Mann's (closed) ! 10 



