November 25. 1922] 



NA TURE 



719 



has to depend on overseas sources for its supply of fuel 

 oil of all kinds, but that the market for fuel oils is not 

 trustworthy commercially, the price having fallen from 

 more than 15/. per ton to from 3^.-4^. during the past 

 eighteen months. " The bearing of this fall in price 

 upon schemes for the low temperature carbonisation 

 of coal will be at once appreciated when it is stated 

 that it represented a drop of at least 10s. on the value 

 of the fuel oil obtainable by carbonisation from 1 ton 

 of coal." At the same time, it must be remembered 

 that in low temperature carbonisation, fuel oils and 

 gas only amount to about 6 to 9 per cent, respectively 

 of the products, 70 per cent, being coke, and the 

 opinion is expressed that the profitable working 

 of the low temperature process must depend largely 

 upon a recognition of the superiority of low tempera- 

 ture coke to raw coal as a fuel, which takes the 

 practical form of willingness to pay a higher price for 

 it. If that were secured so that the process could be 

 adopted by gasworks, it is suggested that the rich gas 

 produced in the process could be brought into use as 

 an enriching agent for the raising of low grade gas 

 made in other ways to a higher standard of calorific 

 value. Plainly, however, any wide adoption of the 

 process would depend upon the difference in price 

 between the solid smokeless fuel and raw coal being 

 small, and the position is summarised thus : " This 

 process as an industrial operation will stand or 

 fall on a perfectly definite issue which is whether or 

 not it is possible to evolve an apparatus on sound 

 engineering lines in' which the capital and working 

 costs would fall within the modest margin of working 

 profit on which the industry must be founded." 



The working out of any such process in its best 

 form depends upon a thorough knowledge of the 

 changes which coal, or rather coals, of different kinds 

 undergo in the process of carbonisation, and the 

 report deals with w-ork on this subject. It includes 

 interesting results which have been obtained in a 

 study of the microstructure of cokes produced from 

 different coals in different ways, and emphasises the 

 value which" attaches to the proper blending of coals 

 for the carbonisation process as influencing their 

 behaviour in the carbonisation process, and the 

 quality of coke which can be produced from them. 

 The work has, however, gone beyond the laboratory 



stage, and experimental apparatus has been devised 

 and worked in which the peculiarities of the low 

 temperature process for good or evil have been 

 brought out. The following results can be taken as 

 typical of those obtained by low temperature carbon- 

 isation in horizontal retorts : 



Yields at 600° ( 

 Coke . 

 Crude oil 

 Liquor 



Ammonium sulphate 

 Gas . 



per ton of Coal (dry) 



r 4"5 to 15-5 cwts. 



13-0 to 17-0 gallons. 



7-0 to 15-0 gallons. 



4-5 to 8-5 lbs. 



3000 to 3500 cub. ft. 

 = 27 to 35 therms. 

 The coke is a smokeless solid fuel, the smoke- 

 yielding constituents having been expelled. The gas 

 is in small quantity but rich. The ammonia yield is 

 very small, about one-quarter of what is usual in 

 gasworks practice. The crude oil is some 50 per 

 cent., greater in volume than would occur in ordinary 

 gasworks practice. Its flash point was atmospheric, 

 and when the light spirit was removed from it so as 

 to give a fairly satisfactory flash point the oil was 

 sufficiently fluid to meet the Admiralty specification 

 at 15 C, but at 0° C. was much too viscous. The 

 crude oil had a limited miscibility in mineral fuel oils — 

 a grave practical shortcoming. The behaviour of the 

 metal retorts used in this carbonisation was satis- 

 factory in the sense that they showed no sign of dis- 

 tortion or depreciation after using for nearly two 

 years, but the behaviour of steel in the moving 

 parts of an automatic carbonising machine which was 

 tried was not equally satisfactory, defects being 

 encountered due to the loss of rigidity which occurs 

 in steel at a temperature of 6oo° C. A number of 

 points requiring further investigation have arisen, 

 and the work now in hand includes the development 

 of automatic methods of carbonisation, the study of 

 briquetting as a preliminary to carbonisation, and the 

 development of a practical method of briquetting at 

 or near the fusing point of the coal. It is along some 

 such lines that it is hoped to arrive at some form of 

 process and appliance for low temperature carbonisa- 

 tion which will meet the technical and commercial 

 demands which have to be satisfied if this method of 

 dealing with coal is to find wide application. 



Expedition to 



A S already announced, the Percy Sladen "irusr 

 -'""*■ Expedition to the Alps of Chinese Tibet, 

 consisting of Prof. J. W. Gregory and his son, Mr. 

 C. J. Gregory, has returned after a successful journey. 

 The primary object of the expedition was the investi- 

 gation of the geological structure of the mountain 

 regions of China in localities which would throw light 

 on the relations of the mountains of south-western 

 China to those of the Himalaya and south-eastern 

 Asia. The expedition left Bhamo on the Irrawadi 

 in North Burma on May 7, and crossed the frontier 

 hills to the " Treaty Port " of Tengyueh, where the 

 Indian servants were sent back and a Chinese staff 

 and muleteers engaged. Permission was there given 

 by the Chinese magistrate to go to Likiang-fu, the 

 administrative headquarters on the borders of 

 Chinese Tibet. The expedition was allowed to pro- 

 ceed to Likiang-fu by a route across one of the blank 

 areas on the existing map of Yunnan. 



At Likiang-fu it was found that orders had been 

 received from the capital of the province that the 

 expedition was not to be allowed to go farther north ; 

 but the magistrate ultimately agreed to its going 

 on if he were relieved of personal responsibility by 

 a letter stating that the expedition was proceeding 

 at its own risk, and in spite of his warning. From 



NO. 2769, VOL. I IO] 



Chinese Tibet. 



L,ikiang-fu it travelled through the valleys of the 

 Yangtze-kiang and the Mekong. Work in the upper 

 Salween valley was found to be impossible, as it was 

 reached in a district smitten with famine owing to 

 the excessive rains of the previous autumn. The 

 return journey to the caravan, which had been left 

 to proceed north along the eastern side of the Mekong, 

 was by forced marches on short rations. At Atuntze 

 excursions were made to the higher mountains 

 between the Mekong and the Yangtze-kiang and to 

 the glaciers of Pei-ma-shan. The return route was 

 through Likiang-fu to the city of Tali-fu and thence 

 by the main trade route across Yunnan to the starting- 

 point at Bhamo. 



The geological collections will, it is hoped, be 

 worked out during the winter, and the results of the 

 expedition can now be judged only by the field 

 evidence. It indicates that while the structure of 

 the foundation of the country is due to the Hercynian 

 movements of upper Palaeozoic date, the area has 

 been affected by a series of uplifts which, both by 

 direction and date, belong to a continuation of the 

 Himalayan system into south-western China. Various 

 botanical and zoological collections were made, most 

 of which are being examined at the Natural History 

 Museum, London, and the Indian Museum, Calcutta. 



