October io, 1901] 



NA TURE 



the often very primitive ideas of comfort and convenience that 

 seem to be possessed by the great railway monopolists ; and 

 we hope, and believe, that it will be the function of electric 

 tiaction to produce as great a change in the comfort of travelling 

 in the present century as did steam railways in that which has 

 just closed. 



The Electrician announces that the Hon. A. Lyltelton has 

 been appointed by the Board of Trade as arbitrator lo settle 

 the dispute between the Metropolitan and District Railway 

 Companies as to the electrical equipment of the Inner Circle. 

 The disagreement has been long and bitter, and, as the Electrician 

 points out, has not only unnecessarily delayed the improvement 

 of the Inner Circle, but has also created an impression that 

 electrical engineers are undecided upon the question of the most 

 satisfactory system of electric traction. That this is true in its 

 broadest sense is no doubt the case, but there are many 

 thoroughly satisfactory systems from which to choose, and it is 

 to be hoped therefore that it will not now be long before one is 

 selected and the alteration of the Inner Circle begins in real 

 earnest. 



The New York Electrical World and Engineer iox September 

 28 contains a long article descriptive of the Cooper-Hewitt 

 mercury vapour lamp. A brief description of this lamp was 

 given in Nature (May 9, p. 39) at the time it was first ex- 

 hibited in America. The present article is founded on the 

 con tents of ten patents just issued to Mr. P. Cooper-Hewitt, and 

 describes in considerable detail the construction and manufacture 

 of the lamps. The chief difficulty met with is apparently in 

 starting the lamp ; it is found, however, that a small amount of 

 sulphur introduced into the tube (as sulphide of mercury) makes 

 it much easier to overcome the initial high resistance, but even 

 with this addition a transformer or induction coil is still needed. 

 Once lighted, the lamp is said to burn steadily on lOO-volt or 

 200volt circuits. The unpleasant colour of the light from 

 mercury vapour can be cured, according to the inventor, by the 

 use of nitrogen in the lamp, this adding the necessary red rays. 

 When originally introduced, the consumption of energy was given 

 as only half a watt per candle, a value which is astonishingly 

 small. We await, therefore, with the greatest interest some 

 account of the practical performance of the lamp ; unfortunately, 

 it is often a big wait from the patent to the commercial lamp, 

 and it can only be hoped that in this case the time will not be 

 over long. 



The general report on the operations of the Survey of India 

 for the year 1899-1900 shows that the total area triangulated 

 was 41,110 square miles, including 16,000 square miles triangu- 

 lated in connection with reconnaissance surveys, and valuable 

 scientific observations were effected in the determination of 

 latitudes. The Government of India, in a resolution reviewing 

 the report, notice with interest the large addition to the 

 geographical knowledge of Yunnan and the north-eastern j 

 frontier, and acknowledgment is made of the efficient way in 1 

 which the work of the department has been carried on. \ 



Some stir has been made in connection with " Kent coal " 

 by the proving in another boring at Dover of certain coal-seams 

 which in reality were discovered some twelve years ago. The 

 original coal-boring was commenced as far back as 1SS6, and a 

 depth of more than 2000 feet was ultimately reached. The fact that 

 another boring in the immediate neighbourhood has been carried 

 to a depth of 1 1 94 feet is of no particular importance. What is 

 required is that the shaft should be completed down to the 

 workable coal, and the information with regard to this (given 

 in the Financial Times of October 4) is that it is hoped to bring 

 up coal " in about fifteen months' time." That the e.\istence 

 of the "coal-field" has been proved "beyond reasonable 

 NO. 1667, VOL. 64] 



doubt " will not be questioned ; the extent of it remains to be 

 proved. There may be small isolated tracts of faulted Coal 

 Measures, or a continuous field extending ten miles or more. 



The Geological Survey of Egypt has just published ai> 

 account of Dakhla Oasis by Mr. Hugh J. L. Beadnell. This 

 oasis lies to the south of that of Farafra, an account of which 

 was previously published (Nature, August 8). It is by 

 far the most important of the four great oases of the Libyan 

 Desert, on account of the number of its inhabitants, the extent 

 of its cultivated lands and palm groves, and the copiousness of 

 its water-supply. The water-supply is derived from an under- 

 ground bed of sandstone, which is never visible. This is over- 

 lain by a bed of red clay and underlain by black clay. The 

 water appears to flow to the surface entirely through artificial 

 wells and bore-holes, ancient and modern. Many of these 

 artesian wells were made during the Roman occupation of the 

 country, some are still in thorough working order, and they are 

 as deep as those bored recently, about 140 metres. The tem- 

 perature of the waters varies from 78° to 102° F., the heat being, 

 due to the depth from which they arise and being modified by 

 local conditions. The water-bearing strata belong to the Nubiarh 

 Sandstone series (Senonian or Upper Cretaceous). They are 

 overlain by a great thickness of soft Danian beds capped by 

 hard white chalky (Danian) limestone. After the hard capping, 

 had been eroded further waste proceeded rapidly, and the forma- 

 tion of great depressions, without drainage outlets, has been due 

 mainly to wind erosion. 



The eruptive rocks of the neighbourhood of Menerville, 

 Algeria, form the subject of an elaborate essay by MM. Louis" 

 Duparc and Francis Pearce, to which Dr. E. Ritter has con- 

 tributed particulars of the geological structure of the country 

 (Mem. de la Soc. de Pkysii/ue et d'Hist. Nat. du Genh'e, xxxiii. 

 part 2, 1901). Special attention is given to the liparites and 

 dacites and to their relations with the granitoid rocks (tonalites 

 and micro-tonahtes). In the same volume, M. P. de Loriof 

 describes some new echinoderms, including Pygurus froirr 

 Cenomanian and Echinolampas from Oligocene strata, and a 

 number of recent species of Astropecten, &c., from various parts 

 of the world. 



In the Proceedings of the Royal Society of Victoria, vol. xiv. 

 part I (August, 1901), geology dominates. Various trachytic 

 rocks are described by Mr. J. Dennant, while the older Tertiary 

 mollusca are in course of description by Mr. G. B. Pritchard, 

 who contributes an account of the lamellibranchs (part 2). 

 There is also a short article by Mr. T. S. Hall on the stages of 

 growth in modern trigonias, which exhibit considerable varia- 

 tion both in the shape of their shells and in their ornament. 



In 1895, a gravitational survey of the kingdom of Wurttem- 

 berg was commenced, and ten stations for the purpose were 

 selected in the first instance on the meridian of Tubingen. The 

 first definite results were obtained in 1899. Dr. K. R. Kocb 

 now describes the results of redeterminations made by pendnlun> 

 methods in 1900, and publishes an account of the methods 

 adopted for eliminating errors of experiment and observation. 

 With the exception of one station, the observations of 1899 and 

 igoo agree to within about two millionths of the observed 

 values. 



A DISTRICT which is free from malaria, in spite of the fact 

 that species of Anopheles are abundant and all the conditions 

 are favourable to the occurrence of this fever, forms the subject 

 of a paper by Dr. Grassi in the Atti dei Lincei, x. 6. The 

 district is that of Massarosa, about eight kilometres from Via- 

 reggio. This district is largely given over to rice cultivation, 

 and, among other noteworthy points, Dr. Grassi finds ( I ) than 

 malaria formerly existed in .Massarosa, but has now practically 



