;66 



NA TURE 



[April i6, 1908 



results, the declinatiun at Alexandria has decreased from 

 13° to 3° west, and the dip from 47° to 42°, in the last 

 100 years. The lines of equal declination at present run 

 nearly parallel to the Red Sea, where the declination is 2°. 

 At the Victoria Nyanza it is 7°. The lines of equal dip 

 run east and west, the dip being 43° north at Port Said 

 .and 23° south at the Victoria Nyanza. The horizontal 

 torce varies from 0.30 at Cairo to 0-35 at Aden, and the 

 curves of equal force are not unlike ellipses with their 

 major axes east and west and their centres in the Gulf of 

 Aden. 



A P.'VPER on " The Possibility of a Topography of the 

 Air, based on Balloon Observations with Special Theo- 

 dolites," by Captain C. H. Ley, appears in the last issue 

 of the Quarterly Journal of the Royal Meteorological 

 Society (vol. xxxiv., No. 145). The paper forms a further 

 contribution to the investigation of the upper atmosphere, 

 which now plays so important a part in meteorological 

 work. In all experiments hitherto made to determine the 

 motion of the upper air from the drift of pilot balloons, it 

 has been necessary either to observe the motion of the 

 balloon through two theodolites at either end of a measured 

 base line, or, if only one theodolite was available, to 

 assume a value for the upward velocity of the balloon. 

 In the present experiments only one theodolite was used, 

 and the remaining data necessary for determining 

 successive positions of the balloon were obtained from 

 measurements of its apparent diameter made with a special 

 twrangement of cross-wires in the eye-piece. Allowance 

 was made for the expansion of the balloon by assuming 

 approximate values for the rate of decrease of tempera- 

 ture and pressure with height, and calculating the 

 volume of the balloon from the usual laws for the 

 expansion of gases. The experimental and other difficul- 

 ties which arise are considerable, and it can hardly be 

 claimed that the author has succeeded in overcoming them 

 ■completely, but the advantages of a method which dis- 

 penses with a second theodolite are considerable, and it is 

 to be hoped that the experiments will be continued. The 

 results obtained go to show that the ascensional velocity 

 of a pilot balloon is far from uniform, as is generally 

 assumed in experiments with only one theodolite. The 

 most striking variations were found to occur as the balloon 

 passed over a ridge of hills. In the vast majority of cases, 

 when this occurred a marked increase in the rate of ascent 

 was observed as the balloon approached the ridge, even 

 though it was at an altitude of several thousand feet above 

 the summit. The increase in the rate of ascent of the 

 1'alloon is regarded as direct evidence of an increase in 

 the vertical component of the motion of the air in which 

 it floats, so that the topography of the land appears to 

 have a close connection with the vertical motion of the air 

 i-ven up to altitudes of 20,000 feet. 



.Some excellent photographs and drawings of the new 

 < "baring Cross Station of the South-Eastern and Chatham 

 Railway are given by Mr. C. S. Lake in L'Ingegneria 

 h'crroviaria of March 16. It is noted that the quantity 

 ■of steel used in the construction of the new roof was 

 1000 tons. 



The School of Mines at Golden, Colorado, with 329 

 ■'mlents, possesses e.xceptional environment for mining and 



■ 'tallurgy, and the current issue of the school Bulletin 

 vol. iv.. No. 2), published semi-annually by the Technical 



lid Engineering Society, affords evidence that excellent 



ork is being done by the students. Mr. F. H. Cronin 

 ^ ives an outline of the course in steam-power plant design. 

 Mr. D. HoIIis and others contribute an admirable paper 

 NO. 2007, VOL. 77] 



on the electrometallurgical treatment of copper slimes, and 

 Mr. C. D. Test gives an account of the occurrence, pro- 

 duction, and commercial value of monazite. 



An important contribution to the knowledge of thf 

 economic geology of Peru is afforded by a monograph, by 

 Mr. Enrique I. Duefias, on the mineral resources of the 

 department of the Cuzco, forming Boletin No. 53 of the 

 Corps of Peruvian Mining Engineers. Descriptions arc 

 given of the gold washings of the river Nusiniscato, of the 

 nickel and cobalt ore deposits of \'ilcabamba, of the 

 .Silurian gold veins in Paucartambo, of the oil fields of 

 Pallpata and Pusi, of the Tertiary and ilesozoic coal- 

 fields of the department, of the iron-ore deposits of 

 Chumbivilcas, and of veins of copper sulphide, argent- 

 iferous galena, gold quartz, and stibnite in various parts 

 of the department. The occurrence of mica in pegmatite 

 dykes, of asbestos, of tripoli, and of other non-metallic 

 minerals of economic value is also recorded. 



At the Institution of Mechanical Engineers on March 27, 

 papers were read by Dr. F. J. Brislee on combustion pro- 

 cesses in English locomotive fire-boxes, and by Mr. L. H. 

 Fry on combustion and heat balances in locomotives. Dr. 

 Brislee's object was to ascertain what percentage of 

 carbonic oxide escaped unburned, and to this end he carried 

 out interesting trials on the London and North-Western 

 Railway. Mr. Fry gave selections from the data pub- 

 lished in " Locomotive Tests and Exhibits, Pennsylvania 

 Railroad," at the St. Louis Exhibition, a book which was 

 issued in 1905. Both papers represent a great deal of 

 labour, and the carefully tabulated experimental results 

 will undoubtedly prove of permanent value, although 

 it is doubtful whether either paper is likely to affect loco- 

 motive practice. 



At the last meeting of the Institution of Engineers and 

 Shipbuilders in Scotland, Mr. M. Kahn read a paper on 

 the practical application of reinforced concrete. He ex- 

 pressed the opinion that reinforced concrete was the best 

 form of construction when properly handled, and the worst 

 when improperly handled. Such being the case, it behoves 

 the owner and the architect to ensure that only the best 

 class of contractor is employed on his work. Contractors 

 can only afford to carry out work which will ensure them 

 a fair amount of profit, and if, by the adoption of re- 

 inforced concrete, the owner is saved 10 per cent, of the 

 cost of construction, it is advisable to grant the contractor 

 any extra saving, so as to ensure his giving a construc- 

 tion which will prove satisfactory in everv respect. When 

 owners and engineers realise this point, and act accord- 

 ingly, reinforced concrete will then reach that position in 

 the category of structural materials where it justly belongs. 



The preliminary official report on the mineral production 

 of Canada in 1907 shows that the total value of the out- 

 put was 86,183,477 dollars, the largest total ever reached. 

 Compared with the production of the previous vcar, there 

 are some decreases to record, such, for instance, as in 

 gold and lead, in corundum, felspar, and graphite, but 

 these are more than counterbalanced by large increases in 

 the production of pig iron, silver, asbestos, coal, natural 

 gas, petroleum, and cement. 



A REPORT on the work and results of the Khatanga 

 Expedition, organised in 1905 by Dr. F. Schmidt, with the 

 cooperation of the Russian Geographical Society, appears 

 in the February number of La Gt'ographie. The work of 

 the expedition was divided into three sections — the ex- 

 ploration of the higher course of the Khatanga, and its 

 relations with the tributaries of the Yenisei; the discovery 

 of the main features of the lake region, and the course of 



