20 



X. I TURE 



[November 2, 1905 



Scottish Antarctic Expedition, was read at Cape Town. 

 Two new buntings, a rich marine fauna, and three new 

 species of plants were obtained. The desirability of further 

 exploration from South Africa was pointed out. In the 

 course of the discussion it was suggested that a meteor- 

 ological station on Gough Island might be of use to South 

 African weather services. Mr. Yule Oldham gave a 

 summary of the history of the discovery of the coasts of 

 Africa, illustrated by an admirable selection of lantern 

 slides of contemporary maps, showing the various stages 

 in the progress of discovery. The proceedings at Johannes- 

 burg were opened by Mr. Douglas W. Freshfield, who de- 

 scribed the Sikhim Himalayas, and the route followed by 

 our troops towards Lhasa ; this was the only other record 

 ul travel. Mr. Freshfield delivered one of the evening 

 lectures at Durban, choosing for his subject " Mountains." 



Some interesting discussions took place on questions of 

 physii al geography at a joint meeting with the geological 

 section, an account of which will shortly be published. 

 At Johannesburg, Prof. Davis, of Harvard, communicated 

 a paper on the geographical cycle in arid areas — a deduc- 

 tive essay based on observed facts. Starting from sugges- 

 tions in Prof. Passarge's great work on the Kalahari 

 Desert, he traced the probable sequence of land forms in an 

 elevated and arid region rarely subjected to water erosion, 

 illustrating his remarks by admirable blackboard sketches. 

 He pointed out that, starting with a rough, uneven land, 

 the occasional water erosion would not be related to sea- 

 level, and .11 an early stage the depressed areas would be 

 slowly filled up, forming lakes of rock waste. In course 

 of time, the slopes would be so worn down and adjacent 

 basins so filled that one communicated with its neighbour. 

 Ultimately a large *' integrated" basin would be formed; 

 wind action would increase with smoothness, and might 

 even transport waste outside arid area. This would waste 

 the whole surface and reduce it to a common level, and 

 wearing away by wind might even lower the surface below 

 sea-level. It was suggested that wind erosion might 

 explain the pans of the Transvaal, the origin of which had 

 occasioned considerable speculation. 



Two papers were of special interest to teachers of geo- 

 graphy. Captain Ettrick W. Creak, F.R.S., vice-president 

 of the section, maintained that the use of globes was 

 essential in teaching geography, and that systematic lessons 

 should be given with globes. 



Mr. J. Lomas showed how excursions could be used in 

 teaching geography, and illustrated his points by views 

 taken on some excursions which he had conducted. 



The committee of the section asked for the re-appointment 

 of the committees on researches in the Indian Ocean, and 

 on the local names given to geological and topographical 

 features in different parts of the British Isles. They, along 

 with sections B, C, and E, asked for the appointment of 

 a committee to report on the quantity and composition of 

 rainfall and the discharge of lakes and rivers in different 

 parts of the globe. 



The whole journey from England to the Victoria Falls 

 and back may be regarded as the longest, most interesting, 

 and most profitable geographical excursion ever made by 

 the section. This has been described in Nature by another 

 pen, and so need not be recapitulated her,., in South 

 Africa the most elaborate special excursions were those 

 arrangi d by the geologists, and the long trek from Pretoria 

 to Mafeking. These permitted members to see the country 

 more intimately than was possible from the train. The 

 thanks of those geographers who were allowed to take 

 part in these must be recorded. 



Since the above was written, the sad news has come that 

 the president of the section. Admiral Sir William Wharton, 

 died at Cape Town on Thursday, September 28, after a 

 short illness. The value of the proceedings in this section 

 was greatly increased by his intimate knowledge of many 

 parts of the world, by his keen interest in all geographical 

 problems, and by the genial way in which he induced those 

 present to take part in the discussions. An account of his 

 career was given in Nature of October 12 (p. 586), but the 

 writer may be permitted to say how very much the success 

 of the meetings of the geographical section was due to the 

 president, whose loss will be deeply deplored by all who 

 were privileged to come in contact with him. 



no. 1879, VOL. 72>~\ 



THE CHELSEA POWER STATION. 1 

 THE development of electric traction as applied to rail- 

 , in Great Britain is about to make one more 

 step forward with the electrification of the underground 

 railways in London, and as this scheme is almost com- 

 plete, a short description of the power scheme may be 

 of interest. 



In most large power schemes that have been completed 

 during the last few years, it has not always been con- 

 venient to place the main power station near the centre 

 of the system of power distribution, owing to cost of 

 ground, &c, but this difficulty is got over by employing 

 a number of small distributing stations which are con- 

 veniently situated in the area of supply, and are supplied 

 with power from a large main generating station. 



The main generating station of the underground electric 

 railway will supply the entire power necessary for the 

 working of the Inner Circle, which it is working in con- 

 junction with the Metropolitan Railway Company's station 

 at Neasden, and for the whole of the District Railway. 

 It will also furnish power to the Baker Street and 

 Waterloo, and the Great Northern, Piccadilly, and 

 Brompton tube railways on their completion. 



Coal for the boilers' furnaces is lifted out of barges by- 

 two large cranes, each working a 27-cwt. grab bucket, 

 which deposits it in a holder where it is automatically 

 weighed. From the holders the coal is carried by means 

 of automatic conveyors to the coal bunkers, which are 

 situated in the top of the boiler house immediately over 

 the boilers. '1 he coal falls from these through chutes to 

 automatic stokers as required, and as the ash accumulates 

 beneath the boiler furnaces it is removed by means of an 

 ash railway. Thus the handling of the coal is almost 

 wholly automatic from the moment the coal leaves the 

 barges until it is returned to the barges as ash. 



The boiler house consists of a basement and two floors, 

 and is 450 feet long by 100 feet wide. In the basement 

 there are eight pumps for pumping the water into the 

 boilers. The boilers are on two floors, each containing 

 thirty-two boilers, with floor space available for eight 

 more boilers on each floor should they be required. They 

 are divided into groups of eight, and each group supplies 

 steam direct to the steam turbine engine to which it is 

 permanently connected. Each group is fitted with 

 economisers for heating the water before it is pumped into 

 the boilers. 



The main engine-room is 75 feet wide by 450 feet long, 

 and consists of a basement and one floor. 



The eight horizontal steam turbine engines are each 

 coupled direct to a three-phase alternating current 

 generator, and it seems hardly conceivable that each one 

 of these sets is capable of transforming the heat energy 

 of the coal into electrical energy equivalent to 7500 horse- 

 power, while the total output of the station is 76,000 horse- 

 power. The electrical generators are of the fixed armature 

 type, having a four-pole revolving field, and generate 

 at a pressure of 11,000 volts. A system of forced lubri- 

 cation is employed on the turbines, thus ensuring efficient 

 lubrication. 



In addition to the above, there are four high-speed 

 engines of 175 horse-power connected to generators which 

 supply the magnetising current for the revolving fields. 

 The condensing system for condensing the steam after 

 it has performed its useful functions in the engines is very 

 ingenious, and is so arranged that the pumps for pumping 

 the cooling water through the condensers have merely to 

 overcome the friction of the pipes. 



One of the most interesting features of the whole system 

 is the switch-board and control system. The system 

 employed aims at having the entire control of the gener- 

 ating in a small space, and at the same time having no 

 dangerous voltages on any part of the control board. 



The system is almost analogous to the nervous system 

 of the human body, having the control board as the 

 brain, which it virtually is. All the big high-voltage 

 switches are operated by small electric motors, and it is 

 these motors which are operated from the control board, 

 and as a low-voltage current is used for this purpose' 



1 Abstract of a paper read before the students' section of the Instnutio 

 of Electrical Engineers by Richard F. Chaffer. 



