226 THE COLLIERY GUARDIAN. February 1, 1918. Table 1.—Showing the Close Agreement of a Series of Samplks of Crude Benzol produced by the Same Plant. Retort test. Distillate at: Flask test. Distillate at: r f . a □D 120° C. 160°C. 84° C. 90° C. 100° C. 120° C. 130 C. 16 ... 56 ... . 69’0 . .. 6’0 .. . 28 ... 53 0 ... 69*0 ... 71’0 17 ... 56 ... . 70’5 . .. 4*5 .. . 30 ... 54*0 ... 68*5 ... 71'5 18 . ... 56 ... , 69*0 . .. 6’0 .. . 28 ... 53’0 ... 67’0 ... 71’0 38 . ... 62 ... . 75*0 . .. 9’5 .. . 36 ... 59'5 ... 72'5 ... 76*0 39 . ... 62 ... . 75’0 . .. 9’5 .. . 36 ... 59’5 ... 72’5 ... 76’0 40 ... 62 ... . 75-0 . .. 6’0 .. . 31 ... 56’5 ... 71’0 ... 75’0 41 , ... 62 ... . 76'0 . .. 8*0 .. . 30 ... 58’0 ... 73’0 ... 77’0 42 . ... 62 ... . 75*0 . .. 6'0 .. . 31 ... 56’5 ... 71’0 ... 75’0 All results expressed as percentages by volume. Many tests have been carried out, and a series of results covering the whole range are given in Table 4. in the larger proportion of distillate obtained at 90 degs. in the flask test above described. The results obtained enable the following conclu- sions to be arrived at: — (1) The criticism that the retort test is not reliable does not seem to be borne out if it is carefully carried out, under uniform conditions and the proper correc- tions applied to the thermometer reading. (2) The retort test has limitations, and these are clearly shown. It fails to show in what respect a par- ticular benzol is abnormal and gives little insight into the relative proportions of benzene, toluene, and xylene in a sample. Referring to Table 2, the results of sample No. 3 show a much larger percentage of distillate at 90 degs. Cent, in the flask test than was obtained with a set of samples of which No. 4 is representative. That was due to sample No. 3 containing an abnormally large proportion of benzene. Table 2.—Showing the Limitations of the Retort Test. Sample No. Retort test. Distillate at: Flask test. Distillate at: A 84° ( J. 90° C. 100° c. 120° C. 130° C. 120° C. 160° C. 3 ... . 46’0 .. . 69’5 .. — ... 24 .. . 45’0 . .. 66’0 . .. 70’0 4 ... 46’0 ... . 62’5 .. — ... 17 .. . 42 0 . .. 59’5 . .. 64’5 42 . . 62’0 .. . 75’0 .. : 6-o ... 31 .. . 56’5 . .. 71’0 . .. 75’0 43 ... 62’25... . 79’25 .. . 6’5 ... 23 .. . 50’5 .. .. 72’0 . .. 76’5 All results expressed as percentages by volume. Such information is valuable for the control of a rectification plant, and is easily obtained from an inspection of the results of the flask test. The reading at the interruption point 80 degs. Cent, in the flask test is serviceable as an indication of the proportion of carbon disulphide in a sample. Thus, taking a series of samples from four different plants, the results in Table 3 show the differences in composition as revealed by the flask test, and the test of the resulting benzol after rectification. Table 3.—Showing the Proportions of Carbon Disulphide Present in'Different Samples of Crude Benzol. 6 Retort test. Distillate at: Flask test. Distillate at: Test of recti- fied benzol. 'ft a 6 o d d d d d d id od cd co O ci r-< . o ' CO Cl S 1—1 o o CM CO r-H r-< *0)0 fH OO o ca W00 53 . ... 63’5...77’75 .. . 9’5 .. .. 26’5 .. . 54’0 . .. 73... 78. p.c. .. 9’5 . p.c. .. 87 54 . .. 63’5...78’75 .. . 9’0 . .. 31’5 .. . 55’0 . .. 72... 76. .. 7’0 . .. 95 59 .. 65’0...78’5 .. . 13’5 . .. 34’5 .. . 60’0 . .. 74... 78. ..19’0 . .. 88 62 . .. 65’0...77’0 .. . 6’0 .. .. 36’5 .. . 62’5 . .. 75... 78. .. 5’5 . .. 86 All results expressed as percentages by volume. (3) The evidence obtained in this investigation seems to suggest the wisdom of the general adoption of the flask test as supplementary to the retort test, which, although capable of giving concordant results, is insuffi- ciently informative for benzols produced from different plants. No attempt has been made to show the composition of the samples, and the results are intended for com- parative purposes only. Details of a Comparative Method. The aim of the second part of this investigation was to find a simple method of comparing crude benzols of different qualities, and to arrive at a satisfactory method of easily calculating their comparative values. As is well known, crude benzol consists of benzene, toluene, and xylene, with other constituents in small proportions, and a proportion of creosote oil, depend- ing in extent upon the conditions obtaining at the pro- ducing plant. It is obvious that a variation in the proportion of the toluene or xylene content will exer- cise an influence on the percentage strength of the benzol as ascertained in the retort test. Experience shows that in a benzol produced from any particular coal the proportions of these constituents do not vary sufficiently to materially influence the retort test result. It is therefore concluded that the creosote is the principal constituent causing the variation in strength of the crude benzol produced. The method adopted in this investigation has been based upon this Conclusion. The procedure has been to distil off from a sample the constituents valuable as rectified products, and to leave behind the creosote as a residue. The apparatus employed consisted of a Young’s rod and disc fractionating column with 20 discs, a round- bottomed flask, and a Liebig condenser. The gradu- ated cylinders employed were carefully calibrated. The thermometer used was a naphtha thermometer, graduated in half degrees from 90 to 210 degs. Cent. All readings were corrected as previously explained. The fractionation consisted of distilling off all con- stituents boiling below 200 degs. Cent., corrected. This, temperature was settled on after a number of preli- minary experiments. Several were carried out employ- ing temperatures between 180 and 200 degs. Cent. It was found that at temperatures below 200 degs. Cent, the results were not satisfactory, tests of the residual oil showing in some samples the presence of a consider- able proportion of the constituents of heavy naphtha. The distillations were all conducted at a uniform rate of one drop per second from the end of the condenser. The residues consisted of creosote oil having a boil- ing point of approximately 205 degs. Cent., and were heavily charged with naphthalene. Table 4.—Samples from the Same Plant. Results. 6 "ft a Test of crude benzol. raction- ®d O o < Retort test. Distillate at Flask test. Distillate at: cd elow ntage n ar; stOlat O c3 O-fl o »d t » <— ^2 fl o f-l 40 120°C. 160°C. 84°C. 90°C. 100°C. 120°C. 130°C. ® o ft » 65’0 . ..78’5 ... 13’5 .. 34’5 ... 60’0 . .. 74’0 ... 78’0 .. . 88’0 .. . 14’7 62’25. ..79’25... 6’5 .. .. 23’0 ... 50’5 . .. 72’0 ... 76’5 .. . 90’0 . . 14’0 61’75.. ..73’5 ... 11’0 .. .. 36’5 ... 59’5 . .. 71’5 ... 75’0 .. . 83’3 .. . 23’1 63’5 . ..77’75... . 9’5 .. .. 26’5 ... 54’0 . .. 73’0 ... 78’0 .. 86’0 ., .. 17’2 63’5 .. ..78’75,.. 9’0 . .. 31’5 ... 55’0. .. 72’0 ... 76’0 .. . 88’7 .. — 62’5 .. ..78’5 ... — .. 28’0 ... 53’0 . .. 72’5 ... 78’0 .. . 88’7 .. ” 14’2 64’0 . ..77’0 ... 11’0 .' .. 33’0 ... 58’0 . .. 72’5 ... 77’0 .. . 85’3 .. — 66’5 . 81’0 ... 8’5 .. .. 29’5 ... 54’0 . .. 73’0 ... 78’0 .. . 9i)’O .. — 64’0 .. ..81’0 ... 7’5 . .. 25’0 ... 51’5 . .. 70’5 ... 76’0 .. . 91’3 .. — 65’5 . ,.82’25... 10’5 . .. 30’5 ... 55’0 . .. 73’0 ... 78’0 .. . 91’0 .. — 69’5 .. ..81’5 ... 6’0 . . 34’5 ... 61’5 . .. 76’0 ... 80 0 .. . 89’3 .. — 71’5 .. .81’0 ... 14’0 .. .. 50’0 ... 70’0 . .. 79’0 ... 80’5 .. . 85’3 .. — 63’0 .. .77-5 ... 5’0 . .. 26’0 ... 55’0 . .. 71’5 ... 74’0 .. . 85’6 .. — 65’0 .. .81’0 ... , 90 . .. 30’0 ... 55’0 . .. 72’5 ... 76’5 .. . 91’3 .. — 63’0 .. .80’0 ... 3’0 . .. 22’0 52’0 . .. 71’0 ... 77’0 .. . 91’3 .. — 61’0 .. .78’0 ... 3’0 .. . 22’0 ... 49’5 . .. 70’0 ... 76’0 .. . 90’3 .. — 64’5 81’5 ... 10’0 .. . 29’5 ... 52’5 . .. 71’0 ... 76’0 .. . 92’0 .. — 65’5 .. .83’5 ... 7’5 .. . 27’0 ... 52’0 . .. 73’0 ... 77’0 .. . 91’7 .. •— 72’5 .. .81’0 ... 16’0 .. . 45’0 ... 68’0 78’0 ... 80 5 .. . 87’3 .. — 65’5 .. .82’5 ... 10’5 .. . 26 0 ... 53’0 . .. 72’0 ... 76’0 .. . 92’0 .. — All results expressed as percentages by volume. The results of this work have enabled a comparison to be made between various benzols, and have also rendered possible the calculation of equivalence of low- grade benzol to the normal 65 per cent, strength pro- duced at the same plant. There is, however, much scope for an extension of this work by the testing on similar lines of ranges of samples from other works. For the plant from which the tests given in Table 4 were obtained, the graph (fig. 2) makes it possible to correct the quantities of benzol of differing strengths, so that they may be stated in terms equivalent to 65’s, provided the result of the- retort test be known. In the graph nothing is allowed for the extra value of creosote recovered when weak benzols are made, as this would probably be discounted by the extra trouble involved in further treatment and by additional steam used. There is a good deal of difference of opinion as to what strength the crude benzol should be made. Some members of the association have suggested 60 per cent, as a better figure than the present 65 per cent., and others one still lower. There is a danger when severe dephlegmation has to be undertaken to produce 65’s that some naphtha, toluol, and even benzol, may be brought down with the heavier oils. When such is the case it certainly seems better to make a weaker benzol, and the graph enables an adjustment of values to be made. By some who never buy benzol for rectification, or who never have any trouble in making 65’s, it might be argued that the investigation described above is of little value, or it might be further asked: Why should any plant make a product testing as low as, say, 40 per cent, at 120 degs. Cent. ? But those who do either buy or sell will no doubt be glad to have some data to help them in adjusting differences of value when the pro- duct is either above or below strength. Various condi- tions may obtain to cause the production of low- strength benzol—as, for instance, the change of wash oil, a period of low-pressure steam, water in the oil, and repairs to or the furring up of the tubes of a dephlegmator. It certainly seems preferable to go on making a product of inferior quality rather than stop the plant until normal conditions can be resumed. Messrs. J. Hopkinson and Company Limited, patentees and manufacturers of safety boiler mountings and valves, Britannia Works, Huddersfield, notify that their London address (late Imperial House, Kingsway) is now Hastings House, Norfolk-street, Strand. The telegraphic address is “ Valvestem, Phone, London.” SOUTH WALES INSTITUTE OF ENGINEERS. An ordinary general meeting of the South Wales Institute of Engineers was held at Cardiff, on Friday, January 25. Mr. Hugh Bramwell, O.B.E., the retir- ing president, announced that the following gentle- men had been elected office-bearers : —Vice-presidents : Mr. VV. Forster Brown, M.Inst.C.E., Cardiff, and Mr. T. Vachell, A.M.Inst.C.E., Newport. Members of Council:—Mr. W. Thomas, Aberdare; Mr. W. Gascoyne Dalziel, Bath; Mr. D. Hannah, Penarth; Mr. ±. Allan Johnson, Cardiff; Mr. E. W. Gnoercson, Pontardawe; Mr. T. F. Thomas, Llandaff; and Mr. VV. O’Connor, Argoed. New Members. The following were elected to the institute: — Menioers: J. b. Bowman, B.oc., Pontypridd; H. J. carpenter, Pentre itnonaaa; w . 1. J ones, Treorchy; 1. C. Martin, iNew rreciegar; jx. E. Michael, ireiorest; V. Phillips, Urumnn, Mon.; and E. W. Watkins, Waunllwyd, Mon. Associate member: w. K. J. Griffiths, bwanage. Associates: J. 8. Caswell, Ebbw Vale; D. D. navies, Markham, Mon.; W. Elias, Merthyr Vale; D. S. Francis, Pentre ithondda; J. K. Griffiths, Llwynypia; A. W. Hatton, Port Talbot; E. P. Jones, Treherbert; W. J. Meredith, Aberfan. The new president (Mr. J. Fox Tallis) moved a vote of thanks to Mr. Bramwell, who, he said, although one or the busiest men in South Wales in connection with ins own concerns and the work of the Govern- ment, had yet found much time to devote to the interests of the institute during a troublous year. They were all delighted at the honour conferred upon their ex-president by his inclusion in the Order of the Empire. Dr. H. K. Jordan seconded and Mr. W. Stewart supported the motion of thanks, which the meeting carried by acclamation. Acknowledging the compliment, Mr. Bramwell said he had felt as much pride in being president of the institute as in any- thing he had achieved throughout his career. Tunnelling Companies, Royal Engineers. The President said he had been authorised to receive applications for temporary commissions in tunnelling companies, Royal Engineers, and suitable candidates would be recommended by him for appoint- ment. Those selected would undergo a course of instruction of about six weeks duration, and would then be commissioned. The secretary of the institute would furnish forms of application. Lewis Essay. The President further announced that the subject of the Lewis Essay for 1918 (prizes £25 and £5) would be “ Fuel Economy in Power Production or the Utilisation of Waste Heat.” Sir William Atkinson Felicitated. The President congratulated Sir William Atkinson, former superintending inspector of mines for South Wales and Monmouthshire, upon having received the honour of knighthood. The name of Atkinson was familiar to every mining student, and Atkinson’s “Ventilation of Mines” was still a standard work. Sir William, who was very cordially greeted, dis- claimed having any share in the book on mine ventila- tion beyond assisting, when quite a student, in some of the experimental work. He supposed his chief claim to the honour that had come to him was in connection with coal dust research. Anything he might have accomplished in that respect was due to the exceptional opportunities he had had of investi- gating the causes of explosions in mines. He supposed he had had to do with more big colliery explosions than anybody in the country, if not in the world. He was only too pleased to know they were in a fair way to combat the coal dust evil, and that what was once only a theory was now an admitted fact. The recent investigations and experiments with stone dust con- ducted by Mr. G. D. Budge, to which he had called attention in a most valuable paper, were a practical application of the knowledge they possessed as to the properties of coal dust. (Applause.) Institute’s Gold Medal. The President stated that the council had decided to award the Institute Gold Medal to Mr. G. D. Budge for his paper on stone dusting in steam coal collieries. PRESIDENTIAL ADDRESS. Utilisation of Iron Ore in Welsh Mines. In the course of an inaugural address, the President said the British Empire was self-contained for almost every mineral substance of economic importance, and the time was ripe for taking an inventory of our mineral resources. It must be remembered that pits in at present populous districts in South Wales were rapidly approaching exhaustion and within the next 50 years would have to be abandoned, as they would not be able to compete with collieries in newer areas. What was to become of the collieries, shafts, and appliances when they became practically exhausted and unworkable at a profit was a serious question of rational importance that should be taken up and dealt with. The collieries that would be first exhausted were those nearest the outcrops, and therefore the more likely to become waterlogged and a danger to the deeper minerals remaining to be worked. The prospect was not a bright one, and might entail the loss of millions of tons of coal of the best quality if the problem was not dealt with in a com- prehensive manner. The question was, could the life of these collieries be extended and maintained at a profit by developing the remaining mineral resources left in the strata? This led up to the very important factor of the iron ore deposits which were at one time