Trans. N. Y. Ac. Sci. 14l» Mar. 13 



neither this, nor any mechanical arrangement of flame, can overcome 

 the difficulty of losing the Ighter vapors in the open apparatus. 



We will now discuss the question of" closed testers." In these an 

 effort has been made, with more or less success, to prevent the escape of 

 the lighter vapors lost in the open apparatus. Tagliabue, who made the 

 first " open tester," has also devised a closed apparatus. In this he 

 has simply placed a heavy brass cover, with a system of valves and a 

 little chimney for igniting the vapors in, upon his open tester. The ap- 

 paratus is not much better than an open tester, and has many draw- 

 backs. First, it is extremely difficult to clean, since the valve-system 

 telow the cover dips into the oil, and it is impossible to clean the ap- 

 paratus after using it with one sample of oil, and before using it with 

 another. Secondly, the results obtained with this apparatus are but 

 slightly lower than those obtained with a good open tester. In using 

 the closed tester of Tagliabue it was noted that the enlargement of the 

 flame took place at almost the same temperatures as in the open testers, 

 the oil not flashing till many degrees above this point, a proof positive 

 that this apparatus does not prevent ihe escape of the lighter vapors of 

 kerosene. This last fact is partly due to the lack of space beneath the 

 cover of the tester and the oil surface. 



Fully realizing the importance of this whole subject, the English 

 government appointed a commission to report upon the question ; and 

 the result of this report was an apparatus devised by Prof. ABEL, the 

 ■chemist to Woolwich Arsenal. Prof. Abel insures the slow heating 

 of the oil by using a large quantity of water and by using an in- 

 termediate air-space between the water-bath and the oil-cup. 

 The oil-cup has a point to be used as a filling-gauge, and is 

 fitted with a tight cover, which carries the flame for ignition of 

 the vapors. This apparatus certainly prevents the escape of the lighter 

 vapors, but unfortunately the ignition lamp which is attached to the 

 cover permanently, and is made of gun-metal, becomes very hot, and 

 by communicating its heat to the cover raises the temperature of the 

 oil at the sides and surface, and produces results that are too low ; /. <?., 

 this apparatus gives "flashing point " much lower than any other I 

 have used, except Mann's apparatus, which I shall speak of later. 



A very ingenious type of " closed tester " is that devised by Bern- 

 stein. This consists of a tube in the form of a letter U, which con- 

 tains the oil to be tested. One limb of this tube is enlarged, and in it 

 is fitted a cap containing two wicks, one central and the other at the 

 side. Around the central wick is a tube communicating with the en- 

 larged limb of the tube below, and the rest of the cap is closed. To 

 operate this apparatus, the limbs of the tube are filled with water to the 

 level of the bottom of the larger end ; into the larger end a measured 



