196 



NATURE 



\June 28, 1888 



and Himyaritic civilizations once adjoined one another, 

 and that their overthrow marked the triumph of the Beduin 

 children of Ishmael. Since Mr. Doughty's travels, Prof. 

 Euting and M. Huber (who was afterwards murdered 

 by the Hharb Arabs) have visited Medain Salihh and 

 Teyma, and carried away with them a large number 

 of valuable inscriptions. One of these, on a stele 

 discovered at Teyma, is now in Paris. 



It is interesting to find Mr. Doughty confirming the 

 statement that the final n of classical Arabic is still 

 pronounced in the Nejd. His remarks on the diseases 

 prevalent among the natives are also curious, though it is 

 difficult to believe that the ophthalmia from which he had 

 himself suffered is due to drinking cold water before 

 going to bed. Everyone, however, who has had much 

 experience of the Beduin will agree with the character 

 he gives of them. The Egyptians have a proverb : "He 

 who shows a Beduin the way to his door will have 

 long sorrow " ; and the traveller is unfortunate who is 

 compelled to intrust himself to their tender mercies. 



A. H. S. 



OUR BOOK SHELF. 



Charts showing the Mean Barometrical Pressure over the 

 Atlantic, Indian, and Pacific Oceans. (London: Published 

 by the Authority of the Meteorological Council, 1888.) 



These charts are issued in the form of an atlas, and 

 deal in a very complete manner with the barometer means 

 and range of all oceans. The months for which separate 

 charts are given are February, May, August, and 

 November, which have been selected to represent the 

 mean values for winter, spring, summer, and autumn 

 respectively in either hemisphere. In addition to the 

 large charts, which give the material in considerable detail, 

 there are four index charts, on a smaller scale, which 

 exhibit for the same months the isobars, or lines of equal 

 pressure, over the entire globe. These are followed by 

 four charts, on the same scale, showing the range of 

 barometrical pressure. The observations have been 

 derived from logs and documents deposited in the 

 Meteorological Office ; logs and remark-books of Her 

 Majesty's ships, furnished by the Admiralty ; published 

 narratives of various voyages, and various published results 

 of other nations ; also observations at coast stations and 

 islands obtained from all available sources. The number 

 of observations obtained from the Meteorological Office 

 logs for the several oceans are : the Atlantic Ocean, 339,300 ; 

 the Indian Ocean, 162,000; the Pacific, 88,300. 



The barometrical means are given in large figures for 

 areas of 5 of latitude by 5 of longitude, and for the 

 benefit of those who require the material in greater detail 

 smaller figures are given to show the means for areas of 

 2 of latitude by 2 of longitude, the several means being 

 obtained from the daily averages. The range to the 

 nearest tenth of an inch for each 5 area is placed over 

 the mean for that area, and the number of observations 

 under it ; so that the charts not only supply the navigator 

 with all the detail he is likely to require, but afford 

 opportunity of the values being combined by other com- 

 pilers with material of a similar nature. The isobars are 

 given for each tenth of an inch, and the free use which 

 has been made of the barometrical values for the coast 

 stations greatly enhances the degree of dependence of 

 the several lines. To facilitate the use of the charts for 

 the navigator, the observations are corrected for a 

 constant altitude of 1 1 feet above the sea, and are reduced 

 to 32 F., but are not corrected for gravity ; a table is, 

 however, given on the face of k each chart to facilitate 

 this correction. 



The general charts which give the isobars of the globe 

 show very conspicuously the prevalence of high-pres- 

 sure areas in each ocean in each of the four seasons. 

 Change is of course shown in the distribution of pres- 

 sure, but there is the same tendency to the persistency 

 of high reading. It is seen that these areas oscillate and 

 alter somewhat in intensity with the season, but there 

 are many characteristics in common. The northern ' 

 Indian Ocean, which is much more surrounded by land, 

 is, however, an exception, the high pressure being situated 

 over the northern part of the ocean, in November and 

 February, and decreasing southwards ; whilst in May 

 and August the pressure is lowest in the north and 

 increases southwards, this change being intimately related 

 to the monsoon winds. The charts of range show well 

 the influence of season, the largest differences occurring 

 in the winter months in each hemisphere. In February 

 the range to the west of the British Islands is 2 - o inches, 

 whereas in August it is only one-half as great. The effect 

 of latitude on the amount of range is very evident, the 

 values near the equator being very small. These charts, 

 which have been compiled by Nav.-Lieut. Baillie, R.N., 

 are considerably in advance of any previous work of a 

 similar nature, and will materially aid in explaining the 

 general circulation of the wind over the globe, barometric 

 pressure and wind being so intimately co-related. 



Commercial Mathematics. (London : Longmans, Green, 

 and Co., 1888.) 



This volume is the continuation of a series of books on 

 commercial education, and specially adapted for can- 

 didates preparing for the Oxford and Cambridge Schools 

 Examination Board. Arithmetic is first dealt with, the 

 first chapter consisting of an account of the decimal 

 system in France. Moneys, weights, and measures, of 

 Germany, Italy, Spain, Portugal, and Russia, are next 

 discussed, followed by numerous examples ; and the first 

 part concludes with a chapter on " Exchange." Algebra 

 is the subject of Part II., which extends as far as quadratic 

 equations, including involution and evolution, and a 

 chapter on the methods of testing algebraical results. 

 The examples are very numerous throughout, and the 

 book ought to be much in demand by the above- 

 mentioned students and others. The volume concludes 

 with a list of results of the various examples. 



A Wanderer's Notes. By W. Beatty-Kingston. In Two 

 Vols. (London: Chapman and Hall, 1888.) 



For about thirteen years Mr. Beatty-Kingston acted as a 

 newspaper correspondent, and in this capacity he had to 

 visit many centres of life on the Continent. In the 

 present volumes he offers a selection from the innumer- 

 able pen-and-ink sketches taken during his " multifarious 

 peregrinations." The work, we need scarcely say, has 

 no strictly scientific interest ; but it is fresh and amusing, 

 and will no doubt give pleasure to many a reader who 

 has never had an opportunity of seeing the places de- 

 scribed in its lively pages. The author is particularly 

 successful in the chapters devoted to Germany, where he 

 seems to have had exceptional means of making himself 

 acquainted with the characteristics of the various classes 

 of the community. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he under- 

 take to return, or to correspond with the writers of, 

 rejected manuscripts intended for this or any other part 

 of NATlTKe. A r o notice is taken of anonymous communi- 

 cations. \ 



The " Sky-coloured Clouds" again. 

 These clouds have reappeared. Last night was the first 

 occasion I have noticed any very distinct display of them 



