August 25, 1892] 



NATURE 



407 



covered for many years, but those launched to the north or the 

 south were thrown ashore more speedily on the coast of France, 

 Spain, Portugal, North Africa, or in the West Indies. The 

 only escape from the whirl was the Gulf-Stream drift towards 

 Norway and the Arctic Sea. The mean rate of circulation was 

 calculated as about 4^ miles per day, and the rate of movement was 

 found to be more rapid in the western than in the eastern half of 

 the whirl. The Prince's second paper set forth the advantages 

 which would accrue to meteorology and to navigation if the atmo- 

 spheric conditions of the North Atlantic could be observed and 

 telegraphed daily to Europe. He pointed out that the Ber- 

 mudas, the Azores, Madeira, the Canaries, and the Cape Verd 

 Islands were, or would very soon be, in telegraphic communica- 

 tion with Europe. If high and low level observatories were 

 established in these islands it would be possible to construct 

 very fair synoptic charts of the North Atlantic, and vastly im- 

 prove upon the useful Pilot Charts now compiled by the 

 Washington Weather Bureau. The Prince was willing that all 

 observations should be collected at Monaco, where the Govern- 

 ment of the Principality would discuss and publish the data, and 

 he suggested that the Governments most interested should send 

 delegates to a conference to be held next winter at Monaco in 

 order to discuss the feasibility of the scheme. Dr. A. Buchan, 

 ill commending the Prince's suggestions, said that the surface 

 temperature of the North Atlantic had been proved to have an 

 influence on the direction of cyclones crossing it, and con- 

 sequently on the weather of the British Islands and western 

 Europe. He thought a properly equipped low-level station on 

 the Bermudas was the first desideratum ; then a similar station 

 on the Azores, to be followed by a high-level observatory. The 

 results at Ben Nevis warranted the expectation of great ad- 

 vances, not only in knowing the weather of the Atlantic, but in 

 forecasting weather for Western Europe, if the Prince's scheme 

 received the encouragement which it deserved. 



Detailed Oceanography and JMeteorology. — Mr. J. Y. Buchanan 

 described his observations on the temperature and density of 

 the water in the Gulf of Guinea in connection with the counter- 

 equatorial current. Dr. H. R. Mill gave a brief account of the 

 physical geography of the Firth of Forth, dwelling particularly 

 on the relation between tidal and solar variations of temperature 

 in the water. The puzzling fact that in the Firth of Forth the 

 water at high tide is saltest when that phase occurs in the after- 

 noon was explained by the high water of spring tides occurring 

 at that hour. Mr. H. N. Dickson, in a short paper, urged the 

 claims of meteorology as a subject of instruction with special 

 regard to its place in physical geography. 



The Desert of Atacatna. — Mrs. Lilly Grove, of Oxford, gave 

 a vivid description of a journey through the Atacama desert, 

 including a trip by rail from Antofagasta to Uyuni at an eleva- 

 tion of 13,000 feet in the Andes. 



Photography and Surveying. — Colonel Tanner explained the 

 system of photographic surveying which he has developed on the 

 Himalayan survey. By the use of a finely ruled grating the 

 angular intervals between prominent objects could be estimated, 

 and in cases where detailed triangulation was impracticable very 

 fair maps could be compiled from photographs taken from 

 several prominent centres. 



Determination of Longitude by Photography. — Dr. H. 

 Schlichter communicated a most important paper, summing up 

 a long series of experiments, and an investigation of the 

 mathematical formulae required in calculating longitude from 

 lunar distances. His method enables him in favourable circum- 

 stances to fix the longitude to within 6", an approximation 

 hitherto only possible by telegraphic time comparisons. His 

 summary is as follows : — 



" Lunar distances as a means for the strictly accurate deter- 

 mination of geographical longitudes have been little used of late, 

 partly on account of the splendid chronometers with which ships 

 are now provided, and partly owing to the inaccuracies of the 

 instruments commonly employed for lunars. For exploring 

 expeditions on land, however, chronometers are of little value, 

 and the other astronomical phenomena which may be used 

 besides lunar distances are either loo difficult for accurate obser- 

 vation by the majority of travellers, or occur too seldom, or are 

 not accurate enough. The author therefore introduces a new 

 method of observation and measurement of lunar distances, viz. 

 by obtaining a parallel series of photographs of the moon and a 

 fixed star or planet on one plate, and afterwards measuring the 

 distances on the plate. For the elimination of all possible in- 

 accuracies of the photographic film or of the lens, the lunar 



NO. II 9 1 , VOL. 46] 



distances thus registered are checked by repeatedly photograph 

 ing on the same plate two fixed stars, the positions of which are 

 given in the Nautical Almanac, and the angular distances of 

 which can easily be computed therefrom. The angular dis- 

 tances of the photographic lunars are then found by a simple 

 proportion. The time for taking a set of eight photographic 

 lunars on one plate does not exceed three or four minutes, and 

 micrometric measurements show with perfect accuracy the change 

 of the lunar distances (owing to the movement of the moon) 

 during each interval of the eight observations. The minute 

 accuracy of the method is hereby established. The micrometric 

 measurements on the plate are made by means of the same 

 rheau which is employed by the principal observatories for 

 stellar photography, and the measurements may therefore be 

 regarded as absolutely correct. Results thus obtained give the 

 correct longitude of the place of observation. The author pro- 

 poses to use this method for scientific expeditions into the 

 interior of continents, &c., as well as for the further determina- 

 tion and correction of secondary meridians in navigation. For 

 both purposes it is especially adapted on account of its minute 

 accuracy and great simplicity." 



African Travels. — The whole of one day was devoted to the 

 reading of papers bearing on Africa, almost all having reference 

 to South Africa. Mr. E. Wilkinson described two journeys 

 which he had made in the Kalahari Desert. Mr. Theodore 

 Bent summarized in an interesting manner the results of his 

 explorations at Zimbabwe ; a paper on the orientation of which 

 was also read by Mr. Swan. In the report of the committee 

 appointed to assist in the exploration of Zimbabwe, it was 

 announced that Mr. and Mrs. Bent intended to pursue their 

 investigations into African ruins of the Zimbabwe type in 

 Abyssinia, Mr. John Buchanan gave an account of the indus- 

 trial resources of Nyasaland, which his long experience there 

 enabled him to do with authority. The fertility of the soil, and 

 the intelligence and willingness to work of the people, were 

 advantages common to few parts of tropical Africa. A staple 

 commodity was still wanting, but there were unmistakable 

 signs that this would before long be found in coffee, which has 

 been grown with great and increasing success. Firm govern- 

 ment of the country, the absolute suppression of the slave-trade, 

 and of intertribal wars, were almost certain to result from the 

 recent extension of the British protectorate ; but the problem of 

 communication remained as a bar to the effective development 

 of the country. With really free traffic on the Zambesi and 

 lower Shire, and a railway, or at least a steam tramway, on the 

 new road from Chilomo to Lake Nyasa, the success of Nyasaland 

 commercially would be assured. Lieutenant Crichton- Browne 

 gave a popular account of a recent journey to Lobengula's 

 capital, and of an interview with that monarch. At the close 

 of this paper Mr. Joseph Thomson, whose health is still in a very 

 unsatisfactory state, made a few remarks, the first he has been 

 able to make in public since his return invalided from Africa a 

 year ago. Dr. A. H. Hallen described the Haussa country, in 

 the language of which he is specially interested. He hopes to 

 be able, under the auspices of the recently-founded Haussa 

 Association, to proceed to the western Sudan, and continue his 

 studies in the country itself. Mr. Ravenstein submitted the 

 report of the Committee on African meteorology, of which Mr. 

 Symons, F.R.S., was secretary. The Committee has collected 

 a considerable number of unpublished records of meteorological 

 observations in tropical Africa, and has charged itself with 

 exercising a friendly influence over existing stations and the 

 equipment of new stations likely to promote a better knowledge 

 of the climatological conditions of the continent. Instructions 

 of an eminently practical kind have been drawn up, and by the 

 circulation of these and the grant of sets of instruments to suit- 

 able observers, it is hoped that the special difficulties of tropical 

 observing may be overcome. The committee has been re- 

 appointed, with the addition of Dr. H. R. Mill as secretary. 



Proposed NrM Map of the Globe.— ^ix. E. G. Ravenstein 

 explained Prof. Penck's scheme of a new map of the world, on 

 the scale of i to 1,000,000, or about sixteen miles to an inch. 

 It was proposed to draw each sheet on an independent projec- 

 tion, the sheets embracing 5° in each direction, except those ^for 

 latitudes higher than 60°, which would have a width of 10" of 

 longitude. The map would be contoured at 100, 300, 500, and 

 1200 metres, hills would be printed in brown, and rivers in blue. 

 The official spelling of all names written in the Roman alpha- 

 bet would be adhered to, accepted names in other alphabets 

 would be transliterated on a system to be afterwards agreed on, 



