November 30, 191 1] 



NATURE 



149 



had some further acquaintance with deductive 

 geometry in the form of riders and later propositions, 

 though in many cases the proofs have been learnt for 

 purposes of reproduction. 



Again, Prof. Carslaw objects to the use of the idea 

 of direction in dealing with parallels and the angle-sum 

 theorem — we should quite agree with him that such 

 a treatment would not be satisfactory in a deductive 

 course, but we difler most strongly from him in 

 thinking that a deductive treatment of parallels, &c., 

 is necessary or wise in the first two years of geometry. 

 The fact is", deductive geometry is not a suitable study 

 for children before the age of twelve, and even at that 

 age it must be a difficult study, and the deductive 

 treatment of congruence and parallels is one of the 

 most difTficult parts of the subject, and should certainly 

 .not precede the deductive treatment of the parallelo- 

 gram and the circle. We can only regret that New 

 South Wales has been frightened by difficulties which 

 were bound to arise in a period of transition, into 

 going back to the old methods instead of boldly 

 remedying the evil by helping all teachers to get the 

 spirit of the new methods. 



The report goes on to consider trigonometry and 

 mechanics, but there is nothing that calls for serious 

 comment. R- Y. S. 



TSETSE-FLIES AND SLEEPING SICKNESS. 



A 



DEPUTATION representing eight missionary 

 societies at work in Nyasaland waited upon the 

 Secretary of State for the Colonies on November 23 in 

 order to urge that game restrictions should be removed 

 over a whole or part of the protectorate, on the ground 

 that the tsetse-fly was suspected of spreading sleeping 

 sickness, and that the destruction of big game 

 "might" eliminate the fly. In his reply, Mr. Har- 

 court very wisely deprecated hasty action in a matter 

 in which " the best-informed people were the least 

 positive as to the facts." 



It is by no means certain that the destruction of the 

 larger mammalian fauna would have any such effect 

 as the members of the deputation seem to anticipate. 

 In the first place, it is highly probable that the primary 

 host of the trypanosome of sleeping sickness is man, 

 and that if the trypanosome is now to be found in 

 wild mammals in regions in which the disease is 

 known to have been introduced in recent times, it is 

 because it has been transmitted to them from human 

 beings by the agency of the tsetse-flies. Secondly, it 

 is very far from certain that the destruction of the 

 larger mammalia would have the efTect of eliminating 

 tsetse-flies, which can suck the blood of any kind of 

 vertebrate animal, and which swarm in parts of the 

 Uganda Protectorate (for example, on small unin- 

 habited islands in the Victoria Nyanza) where there 

 are no larger mammalia. Thirdly, the danger must 

 be reckoned with that to deprive the tsetses of a large 

 portion of their natural food-supply might have the 

 effect of forcing them to supplement the deficiency 

 elsewhere, and might therefore render them much 

 more aggressive towards men and domestic animals, 

 and in this way more efficient in spreading trypano- 

 some diseases. 



Everyone with a knowledge of the complicated 

 problems involved in the subject of the transmission 

 of trypanosomes by tsetses will deprecate ill-considered 

 destruction of the big game, an action which, while 

 robbing large tracts of country of one of their most 

 beautiful and valuable features, may very well have 

 the effect of upsetting the balance of nature in a 

 manner that would greatly aggravate the evils which 

 it is desired to combat. 



NO, 2iq6, vol. 88] 



THE INTERNATIONAL CONFERENCE AT 

 PARIS ON NAUTICAL ALMANACS. 



ON the initiative of the Bureau des Longitudes, the 

 directors of the various national ephemerides 

 were invited by M. Baillaud, director of the Paris 

 Observatory, to assemble there on Monday, October 

 23. The objects of the reunion were to consider 

 what steps, if any, should be taken to extend 

 the scope of the various ephemerides for the purposes 

 of astronomy, and at the same time to effect economy 

 by combined action and interchange of computations. 

 A small number of the leading practical astronomers 

 were also invited to represent the needs of astronomy 

 of precision. 



The first general meeting was held at the Observa- 

 tory at 10 a.m., Monday, October 23. On the motion 

 of Sir David Gill, M. Baillaud took the chair, having 

 on his right M. Bayer, secretaire de I'enseignement 

 sup^rieure, representing M. Steeg, Ministre d'lnstruc- 

 tion publique. 



On the motion of M. Baillaud, Sir David Gill, as 

 president d'honneur du Congres de la Carte du Ciel, 

 was nominated president d'honneur of the reunion. 

 Dr. O. Backlund, imperial astronomer of Russia, vice- 

 president, and Mr. H. Andoyer, of the Bureau of the 

 Connaissance des Temps, together with the Comte 

 de la Baume Pluvinel, were nominated secretaries. 

 There were present : — Prince Roland Bonaparte 

 (member of the Academy of Sciences) ; Messrs. Cowell 

 (" Nautical Almanac," London), Fritz Cohn (Berlin), 

 Eichelberger (Washington), G^n^ral de Azcarate (San 

 Fernando), Boccardi (Turin), as directors of 

 ephemerides; Messrs. Dyson (astronomer royal, Green- 

 wich), Hough (H.M. astronomer. Cape of Good Hope),. 

 Perrine (Cordoba), Andr6 (Lyons), Picart (Bordeaux),. 

 Verschaffel (d'Abbadia), as directors of observatories;: 

 and, as representatives of the Bureau des Longitudes,. 

 MM. Bigourdan (president), Poincar^, Radau, 

 Deslandres, Hanusse. 



The meeting was opened with an admirable address 

 by M. Baillaud, and with a cordial speech of welcome 

 by M. Bayer on behalf of the Minister of Public In- 

 struction. After some discussion, resolutions, recom- 

 mending the adoption as soon as possible of Greenwich 

 mean time as the argument for all predictions in 

 nautical and astronomical ephemerides, were unani- 

 mously passed. In the afternoon of the same day 

 the members of the congress attended by invitation 

 the meeting of the Academy of Sciences at the insti- 

 tute, and in the evening were entertained at a banquet 

 in the Observatory, at which M. Steeg, Minister of 

 Public Instruction, was present. The toast of " The 

 President of the French Republic " was proposed by 

 Sir David Gill, to which an interesting and eloquent 

 speech was made, in reply, by M. Steeg. The health 

 of M. Baillaud was proposed by Dr. Backlund. 



Further meetings of the congress were held on 

 October 24 and 25, and at the conclusion of the meet- 

 ing on October 25 a unanimous agreement on all 

 points was reached. On Thursday, October 26, the 

 directors of the nautical almanacs met in committee to 

 make final cooperative arrangements and report to 

 the general congress ; their report was unanimously 

 adopted at an afternoon meeting on the same day. 



A translation of the resolutions adopted is subjoined. 

 It is impossible to overrate the good will and cor- 

 diality which pervaded the meeting, or the kindness 

 and hospitalitv of our hosts. Besides the official 

 banquet on Monday, private dinner-parties were given 

 by M. Andoyer on the Tue.sday, by M. Baillaud on 

 the Thursday evening, the latter followed by a recep- 

 tion ; a luncheon and reception were also given on the 

 Friday afternoon by Prince Roland Bonaparte, and 



