194 



NATURE 



[Al'RIL 15, 1909 



shall ensure its completion, the present meeting of 

 the permanent committee has a most practical and 

 important duty before it. But it has still further 

 matters of interest and importance to deal with. 



First, as regards the chart and catalogue, it must 

 be remembered that to a great extent the sixteen 

 observatories have been working independently, and 

 it is impossible that, in existing circumstances, these 

 results can be entirely homogeneous. 



For example, at some observatories the diameters 

 of the star-discs have been measured; at others, the 

 magnitudes have been estimated by comparison with 

 sets of photographed images assumed to represent 

 stars of known magnitude. It will be the business 

 of the " Magnitudes Committee " to devise effective 

 means for reducing these measures of diameter and 

 miscellaneous estimates to a uniform and absolute 

 system of magnitudes. Another committee will deal 

 with the sj'stematic errors which have been found to 

 exist in the coordinates of star-images measured in 

 certain series of plates. In some cases these errors 

 depend on the magnitude of the star, in others on 

 its distance and position angle from the centre ol 

 the plate. The optical committee will have to trace, 

 so far as possible, the origin of these errors, and 

 devise means for eliminating their effects from the 

 final results. 



The coordinates of the star-images measured on 

 the plates are of no value for the purposes of funda- 

 mental astronomy unless the system of the coordinates 

 of each plate is referred to a number of stars the abso- 

 lute positions of which on the sphere are known. In 

 the case of some of the zones the places of the refer- 

 ence stars depend on meridian observations, few in 

 number and made a considerable number of years ago ; 

 in other cases they depend on recent but only locally 

 observed zones, ft is essential that not only should 

 adequate provision be made for proper meridian 

 observation of the zones, but also for their coordina- 

 tion to a common system on the plan so far carried 

 out by Dr. Kastner at Bonn. The arrangement of 

 this part of the work will rest with the fundamental 

 stars committee. 



At the last meeting of the permanent committee 

 in 1900, a good deal of time was given to con- 

 sideration of the steps to be taken for the observation 

 of the then recently discovered planet Eros, at its 

 opposition at the end of 1900. The bureau of the 

 committee has published a large number of the 

 observations of Eros that were secured at the opposi- 

 tion of 1900, as well as the results of meridian and 

 photographic observations of the comparison stars, 

 and an accurate ephemeris of the planet for that 

 opposition. The unique characteristics of the orbit 

 of Eros present conditions which are exceptionally 

 favourable for researches of extraordinary astro- 

 nomical interest and importance, viz. for the 

 trigonometrical determination of the solar parallax 

 and mass of the moon, and for the dynamical deter- 

 mination of the mass of the earth by the perturba- 

 tions which it produces in the motion of Eros. In 

 1900 Eros approached the earth within one-third of 

 the earth's mean distance from the sun, but at the 

 opposition of 193 1 it will approach the earth within 

 half that distance, viz. within one-sixth part of the 

 earth's mean distance from the sun. It is not, even 

 now, too soon to begin preparation for this unique 

 opportunity, and accordingly an Eros committee will 

 be appointed for the following purposes : — 



(a) To receive reports on the actual state of the reduc- 

 diictions of the past observations of Eros, and to prepare 

 a report upon them. 



{V\ To take steps for the preparation of an appro.ximate 

 ephempris of Eros at the opposition of 193 1 of sufficient 



NO. 2059, "^'OL. 80] 



accuracy to permit the selection of the most suitable com- 

 parison stars. 



(c) To discuss the best methods of observing the opposi- 

 tion in question, especially with a view to avoid systematic 

 error in the final results. 



(d) To discuss the basis of the choice of comparison 

 stars, and how to ensure their proper observation. 



(e) To devise means for the regular observation of Eros 

 from this time forward in order to perfect the ephemeris 

 that will be finally employed in the definitive reduction of 

 the observations of 193 1, that is to say, for the direct 

 determination of the solar parallax and mass of the moon, 

 and also for the ultimate determination of the mass of 

 the earth by means of the perturbations which it produces 

 in the motion of Eros. 



There can be no doubt that all these objects can 

 only be attained by international cooperation, and 

 that they furnish ample material for an interesting 

 and important meeting. The following astronomers 

 have accepted M. Baillaud's invitation on the part of 

 the French Government to be present on the occa- 

 sion :^ 



Prof. Andoyer, Paris ; Ch. Andr^, Lyon ; M. Angot, 

 Paris ; T. de .Azcarate, San Fernando ; O. Backlund, 

 Pulkova; B. Baillaud, Paris; J. Baillaud, Paris; H. G. 

 van de Sande Bakhuyzen, Leyden ; Le G^n^ral Bassot, 

 Nice; de la Baume Pluvinel, Paris; M. Bayet, Paris; 

 G. Bigourdan, Paris ; G. Boccardi, Turin ; Prince Roland 

 Bonaparte ; F. Boquet, Paris ; H. Bourget, Marseilles ; 

 Sir W. H. M. Christie, Greenwich ; W. E. Cooke, Perth, 

 VV. Australia; M. Cosserat, Toulouse; M. Deslandres, 

 Meudon ; \. Donner, Helsingfors ; F. W. Dyson, Edin- 

 burgh ; John Franklin-Adams, London ; A. Galliot, Paris ; 

 P. Gautier ; Sir David Gill, London ; M. Gonnessiat, 

 .Algiers ; G. E. Hale, Mount Wilson ; M. Hamy, Paris ; 

 A. R. Hinks, Cambridge ; S. S. Hough, Cape Town ; 

 Fernand Jacobs, Brussels; J. C. Kapteyn, Groningen ; 

 E. B. Knobel, London ; M. Kromm, Bordeaux ; F. Kiistner, 

 Bonn; Le R. P. Lais, Rome; I. Lagarde, Paris; \. 

 Lebeuf, Besan^on ; G. Lecointe, Brussels ; G. Leveau, 

 Paris; M. Lumi&re, Lyon; Major P. A. MacMahon, 

 London; J. Palisa, Vienna; C. D. Perrine, Mount Hamil- 

 ton ; L. Picart, Bordeaux ; A. A. Rambaut, Oxford ; 

 H. Renan, Paris; A. Ricco, Catania; J. Scheiner, Pots- 

 dam; M. Sti^phan, Marseilles; E. Strbmgren, Copenhagen; 

 H. H. Turner, Oxford; F. Valle, Tacubaya ; M. 

 Verschaffel, Abbadia ; W. Zurhellen, Bonn. 



DR. ARTHUR GAMGEE. F.R.S. 



HIS numerous friends and fellow-workers in 

 science, both in this country and abroad, will 

 hear with deep regret of the unexpected death of 

 Dr. -Arthur Gamgee, in Paris, on March 29. He 

 was in his sixty-eighth year, and though not a 

 young man was in full possession of an exception- 

 ally endowed intellect which was ever urging him 

 on in the path of research. Throughout a some- 

 what unsettled life his enthusiasm for research never 

 waned from the time of his early student days, when 

 he followed his natural leanings towards original 

 physiological work, to which his exact knowledge of 

 physics and chemistry was to be applied with a 

 success that gained for him a wide and well-deserved 

 reputation. 



To many of the younger physiologists Dr. Gamgee 

 was personally unknown. He was born in 1S41, in 

 Edinburgh, a younger son of Joseph Gamgee, a 

 distinguished veterinary surgeon and pathologist, 

 whose work, particularly that on rinderpest, was 

 well known in England and on the Continent. An 

 elder brother, Joseph Sampson Gamgee, long con- 

 nected with the general hospital in Birmingham, 

 was a man of great mental gifts and remarkable 

 personality, who made a name for himself in his 

 profession, and will be remembered for the introduc- 

 tion of improved methods in the treatment of wounds 



