368 



NATURK 



[January i i, i«)12 



coke; while a« ihs temperature rise* above 750" C, the 

 pitch residue d«'conipo»eg, yielding hydrogen, carbon 

 inonoxidf, imd methane as gases, while the cnrbon r»-sidue 

 from th'- pilch binds the residual mns$ into coke. It is 

 this residual pitch that Burgess and Wheeler have mis- 

 taken for a primary constituent of coal. 



It is clear, however, that (putting detail on one side 

 until our knowledge has been broadened by experience) the 

 answer to the question as to what is the composition of 

 coal — whether the answer is derived from a consideration 

 of the actions taking place during its formation and of 

 the substances from which it was derived, or is obtained 

 fro.n analytical data, as was done by Anderson and 

 Roberts, or from the products of distillation, as has been 

 done by Burgess and Wheeler — must bt.' that coal is a 

 lunglomerate of humus and its degradation products with 

 the resinic bodies and their derivatives. 



(in the second lecture of the series, Prof. Lewes traced 

 the alterations in the methods of carbonisation from 

 .Murdoch's pot stills to the latest forms of gas-making 

 retorts, showing the reasons that led to the horizontal 

 iron retort, its gradual replacement by fire-clay retorts, 

 the introduction of the inclined retort, and the improve- 

 ments in gas settings.) 



Since itJqj, when the advent of the incandescent mantle 

 as a practical method of developing light began to do 

 away with the necessity for gas of high illuminating 

 value, so general became the adoption of the mantle that 

 in i<)oo applications b«'gan to be made in Parliament in 

 various Gas Bills to reduce the standard of light for 

 those companies whose previous average had been about 

 i() candles, it being felt that a 14-candle gas was 

 bptter fitted for yielding light with the incandescent 

 mantle, power in the gas engine, and for heating in 

 gas Steves than higher qualities ; and it also gave the 

 possibility of economies in manufacture, which it was 

 hoped might lead to lowering of the price of gas to a 

 pomt at which it would better compete with fuel gas 

 for power purposes. 



Durinfj the last ten years there has been an amount 

 of activity in attempts to alter the process of gas manu- 

 facture which has exceeded any that has taken place since 

 the first few years of its inception, and this new era may 

 be considered to have start'^d with the inauguration of 

 the vertical retort, in which, by utilising a large oval 

 lire-clay retort set on end with a slight taper from bottom 

 to top, much larger charges could be used than had been 

 possible with the horizontal or inclined retorts, and in 

 which also gravity was utili.sed to the full for charging 

 and discharging. 



The vertical retort dates back to 1828, when it was 

 first introduced by John Brunton, who, finding that the 

 gas could not escape freely from the lower portions of 

 the charge, and so created considerable pressure, put a 

 perforated pipe in the centre of the charge to afford 

 an easy wav of escape. Nothing more was heard of the 

 process, so It probably failed ; but at later dates attempts 

 of the same kind were made by Lowe and Kirkham and 

 also by Scott. 



.\fter these early experiments nothing seems to have been 

 done for sixty years until the sunmier of 1903, when 

 Settle and Padfield put up a vertical retort at Exeter, 

 and Dr. Bueb started experimenting on the subject in 

 Germany. 



\'ertical retorts during the last few years have met 

 with great success on the Continent, and their use has 

 spread with the greatest rapidity. 



In England it has been felt that, good as are the results 

 obtained with the vertical retort working intermittently, 

 i.e., by putting in a full charge of coal, carbonising and 

 drawing, and then recharging in the same way as with 

 the old form of retorts, great improvements could be 

 effected by making the process continuous, as was first 

 attempted by Settle, so approaching more nearly to uniform 

 conditions of carbonisation. Vertical retorts on this 

 principle have been devised by Messrs. Duckham and 

 Woodall, and by Messrs. Glover and West, and they 

 certainly show results which will lead to continuous car- 

 bonisation being one of the most important factors in 

 the future of gas manufacture. 



The economies to be derived from carbonisation in bulk 



NO. 2202, VOL. 88] 



have on the Continent led to ttill further advance* in 

 «tizc of the charge, and little more than three yr-— 

 chamber i .irUmiHaiicm was introduced at .Mir 

 which charges of 3 to 8 tons of coal can t 

 with at a time, and thi» method also has met with a 

 large amount of succe«s, a number of in)>tallations having 

 b«pn erected on the principle* laid down by Rif-s, Kopp< 

 and others. 



.Many ob<er\ers felt that the old horizontal retort covjai 

 be made to yield better results than had hitherto b«en 

 obtain<-d, and Mr. C. Carpenter, at the South Metr<- 

 f)olitan Gas Company's works, found thai great advant. 

 may be obtained by packing the old horizontal retorts • 

 of coal, as had been suggested by Kunath in 1885, instead 

 of only partly fillinti thm, this doing away with the 

 large space that had always been left above the chnrr 

 of carbonising loal, and so eliminating to a great e.v 

 the baking of the gases and contact with the he.ii . 

 crown of the retort, this giving a distinct advance in 

 make and quality not only in the gas, but in the tar. 



Whilst these changes in form have been taking pi. 

 improvements in the settings, gas fuel, and regener.i 

 firing have made such strides that the temperatur's 

 employed are limited only by the nature of the refractory 

 materials used, and the result of these higher temperatures 

 with light charges is to largely increase the volume of the 

 gas obtainable per ton of coal, but at the same time its 

 illuminating value is reduced, and the tar is deteriorated, 

 and it also gives rise to stoppage of ascension pipes and 

 an increase in naphthalene troubles in the service. 



When iron retorts were used, the temperatures that c 

 be employed were limited by the softening point of the ii 

 and rarely rose above 800° C, and although only '. 

 cubic feet of gas were made per ton of coal, the gas v 

 rich in heating and lighting value, and the tar excellent 

 in quality. The advent of the fire-clay retort, as has 

 been seen, enabled temperatures to be increased, and 

 10,000 cubic feet of gas was the general yield. With the 

 introduction of regenerative firing, the volume of c""^ 

 obtained rose to 11.000 cubic feet, whilst the more mo<l 

 dn-lopments approach a yield of 13,000. 



In all these changes the gas manager has been actu. 

 by the desire to get the greatest volume of gas pos~ 

 p»r ton of coal, and at the same time to do it v 

 the greatest economy, and but little attention has \ 

 paid to the quality of the tar and coke, which have 1 

 looked ujxin as by-products. In point of fact, the 

 when temperatures were pressed to their highest in ligi 

 charged horizontal retorts, became so poor and chok <i 

 with naphthalene and free carbon as to be almost valuele^- 



The intrcduction of large masses of coal in carbon' - 

 tion, for reasons which will b" discussed fully later, 

 led to distinct improvements in this respect, and altho 

 there is no modern tar which approaches in value 

 product of the old iron retort, the improvement in m 

 places of late has been very marked. 



(The gradual growth oif the coke-making industry 

 then dealt with from the Meiler heap to the mofi 

 coke recovery ovens.) 



{Jlo be continued.) 



US'IVERSITY .AND EDUCATIONAL 

 INTELLIGENCE. 

 London. — The following are among the courses that will 

 be held in the Faculty of Science at University College 

 during the present term : — " General and Geological 

 -Aspects of Palaeobotany," by Dr. Marie Stopes, on Tues- 

 days at 4 p.m., beginning on January 16: "Instruments 

 and Maps," by Mr. M. T. Ormsby, on Tuesdays at 4 p 

 beginning on January 23; "Vertebrate Palaeontology." 

 Prof. J. P. Hill, on Tuesdays at 5 p.m.. beginning on 

 January 23. In connection with the Francis Gallon 

 Laboratory for National Eugenics, Prof. Karl Pearson will 

 deliver two lectures on " Sir Francis Galton," on Tues- 

 days, January 30 and Februar>- 6, at 8.30 p.m., to b" 

 followed on subsequent Tuesdays by a course of 

 lectures on " Some Problems of Eugenics." 



We learn from the Revue Scientifique that M. Georges 

 Leygues has just given 25,000 francs to the University of 



