170 



KNOWLEDGE 



[August 1, 1898. 



hands, it was replaced in the Act of 1879 by the closed 

 cup, or Abel tester, in which the oil is warmed in a closed 

 vessel, and is only exposed to the air at the moment that 

 the testing flame is applied. A series of tests made by 

 Mr. Boverton Redwood on a thousand samples of American 

 kerosene having proved that the Abel tester showed a 

 flashing point about twenty-seven degrees hirer than the 

 open tester indicated, a " flash point " of seventy-three 

 degrees Fahrenheit was decided upon, so that the actual 

 flash point now recognized may be considered as identical 

 with that originally decided upon over thirty years ago. 



The Abel tester has been found so efficient and regular 

 in the results it has yielded in the hands of difl'erent 

 operators, that it has been legalized in many other 

 countries, either in its original form or with some slight 

 modifications. It is shown in Figs. 1 to 3, and consists 

 of the metal cup, Figs. 1 and 2, into which the oil to be 

 tested is poured up to a fixed point ; an outer metal cup 

 serving as a water bath, and an enclosing metal cylinder 

 forming an air jacket. A lamp swivelled on one leg of the 

 apparatus is also fitted to the tester (Fig. 3), and thermo- 

 meters indicate the temperature of both the oil aad the 

 water. 



The oil cup has three square holes in its cover which 



Fig. 1. Fig. 2. 



Tlu' Abul Tester for the ' 



Fig. 3. 

 Flash Point.'' 



are normally closed by a sliding plate having three corre- 

 sponding openings. The slide is shown closed in Fig. 1 

 and open m Fig 2. It carries a pin, which, when the 

 slide IS opened, catches a small metal lamp swinging on 

 pivots and tilts its nozzle downwards over the surface of 

 the oil through one of the three openings, as shown in 

 Fig. 2. This test lamp consists of a bo.\ with a hinged lid 

 and a tubular nozzle, through which passes a tiny wick 

 from the body of the lamp, which is charged with cotton 

 wool saturated with oil. The wick is trimmed to give a 

 flame exactly the size of the small bead shown at the end 

 of a pin on the oil cup. All parts of the apparatus are 

 made to a standard size, and are tested by the Weights 

 and Measures Department of the Board of Trade before 

 they may be used officially. 



In using the apparatus, the water bath is first charged 

 with warm water through the funnel shown, and the 

 temperature brought to one hundred and thirty degrees 

 Fahrenheit by the addition of hot or cold water or by use 

 of the lamp beneath the apparatus. The oil cup is then 

 charged with the oil to be tested, the little test lamp 

 lighted, the lid of the oil cup closed, and its thermometer 

 watched. A pendulum, twenty- four inches long, is then 

 set swinging, and wlien the temperature of the oil has 



reajhed about sixty degrees Fahrenheit, the test is com- 

 menced. For each degree of rise in temperature the slide 

 is drawn open slowly by hand while the pendulum makes 

 three oscillations, and is closed during the fourth oscillation. 

 When the flashing point is reached, a slight blue flame is 

 seen to pass over the surface of the oil, and if this occurs 

 at a temperature not lower than seventy-three degrees 

 Fahrenheit, the oil is said to have passed the test. 



In the application of this test everything depends on 

 adherence to the specified conditions. Tables for variations 

 in the atmospheric pressure must be used. 



So many testers are or have been in use that it would 

 be impossible even to give their names here, and the Abe) 

 tester has been selected as the one most generally 

 employed. 



For many technical and commercial purposes other tests 

 have to be applied. Thus the analyst must sometimes 

 employ chemical tests to ascertain freedom from sulphur 

 compounds, etc. ; distillation tests to ascertain the amount 

 of the oil which volatilizes between certain temperatures ; 

 colour tests, in which, by means of Lovibond's tintometer, 

 or Wilson's or Stammer's chromometer, the colour 

 according to the commercial standards between " water 

 white" and "good merchantable" is determined; vis- 

 cosity tests, in which the value of the oil as a lubricant is 

 ascertained ; photometric tests to determine the illuminating 

 power of the oil ; and, finally, the odour test, by which an 

 experienced operator can tell whether the oil has been 

 properly refined and kept. 



AN OLD-WORLD HIGHLAND. 



By Grenville a. J. Cole, m.r.i.a., f.g.s., Professor of 

 Geolrxiij in tlie Royal ColUije of Science for Ireland: 



THERE is a corner of wilder Connaught, on the very 

 border of Galway and of Mayo, where the features 

 of the west of Ireland seem grouped together and 

 epitomised. In a brief season of summer it is 

 known to tourists as Leenane ; but, in the more 

 transparent and sunnier days of spring or autumn, the 

 lover of quiet will find it a haven of content. Before the 

 hospitable doorway, the sea stretches in gentle ripplings, 

 at the head of a fjord which runs down west to open water. 

 There is little suggestion here, whether the day be dark or 

 clear, of the great surge that beats ever on the islands, 

 on Inishbofin and lofty Inishturk, ten miles away in the 

 Atlantic. Northward lies the mountain-land of Mayo, a 

 district as large as Sutherland, over-populous on its sea- 

 board, yet wild and desolate within. Southward lies the 

 still finer highland of (lalway, a land of peaks, and 

 terraced moorlands, and abundant lakes, into which even 

 the broad Lough Corrib sends up romantic tongues of 

 water. Except for one encircling road, these fastnesses 

 east of the Twelve Bens, the barren valley of Bealana- 

 brack, or the deep grey hollow of Lough Nafooey, are as 

 little known to most of us as Corsica. 



The remark has some appropriateness, for in these grim 

 surroundings, without communications, girt about by the 

 precipiced cirques of Formnamore, a race has grown up to 

 whom the law of vi'mldta has seemed nearer and far 

 simpler than the complex legality of the east. Cast down 

 by years of failure, weakened by the emigration of the 

 strong, driven by topographical details to repeated inter- 

 marriage, this population has presented the problem of an 

 island cut off within an island. Nowadays the railways 

 have crept nearer to the mountains ; ]5ublic bodies have 

 employed both men and women in turning the unfenced 

 tracks into some of the finest roadways in our islands ; 



