December 9, 1897] 



NA TURE 



129 



ones, would acquire superior authority without justifiable 

 motives. Dr. Auwers, who is undoubtedly the most competent 

 person in such matters at the present time, has well delineated 

 the limits of his fundamental catalogue, calling it not purely and 

 simply fundamental, but " fundamental for the observations of 

 the zones of the Astrottomische Gesellschaft.'" In other words, 

 he has not intended to do anything else than furnish an indis- 

 pensable basis for the great international undertaking about the 

 zones, and has set up a guard against extending the signification 

 of " fundamental " that should legitimise every delicate use of 

 his stellar positions. The researches to which he is attending 

 now, and to which the Paris Conference justly attributes "un 

 interet scientifique de premier ordre," prove how in his mind (as in 

 those of all the astronomers assembled in Paris) the fundamental 

 catalogue now in use may be considered alike provisional, just as 

 the new catalogue to be compiled at the end of this century for the 

 needs of national ephemerides. To give to-day the title and the 

 authority of a fundamental catalogue to a collection of stars is 

 not sufficient in fact for the single stars to answer simply to the 

 conditions which are enumerated at page 6 (Appendix C) of the 

 Annuaire du Bureau des Longitudes for 1897 ; it is necessary 

 that their positions be founded on absolute observations, ex- 

 ecuted with all the precision of which perfected modern instru- 

 ments are susceptible, and on an exhaustive discussion of the 

 series obtained till now on the same stars at Greenwich, Pul- 

 kova, Leyden, Washington, and in a few other observatories. 

 For the present time the needs of the practice will be satisfied 

 with collections like those of Auwers, Boss, Safford, and 

 similar astronomers. 



After all, if an international accordance were proposed ex- 

 clusively to cause the four great ephemerides to adopt a uniform 

 system of constants and of fundamental stars (as it appears to 

 have been decided at Paris), without taking care at the same 

 time that the reasons for the preference granted to such a system 

 should consist in the undeniable superiority of it with regard 

 to every other pre-existing, one might say that the agreement 

 shows the absurdity of losing time, labour and money in the 

 compilation of four different ephemerides, whilst one alone is 

 enough for the needs of astronomy and navigation. In fact, for 

 what object are four separate bodies of calculators employed to 

 draw from planetary tables the places of the sun, moon and 

 other bodies of our system ? Would not one office alone, even 

 international, be more than enough, and one sole almanac, pub- 

 lished in several languages ? And would it not be convenient 

 to profit by the occasion to separate more clearly than has 

 hitherto been done what is necessary for astronomers from that 

 which is sufficient for geodetical observers, for geographers, for 

 sailors? The papers in the Astrotiomical yournal touch this 

 matter with great ability, calling attention to the fact that the 

 national ephemerides (except, perhaps, that of Berlin) show 

 rather too much the effects of their practical destination ; if this 

 could be fused with the supreme scope of astronomy some 

 centuries ago, when the decay of astrological tendencies obliged 

 science, from reasons of self-preservation, to find for herself a 

 utilitarian basis, it is not at the end of the nineteenth century 

 that she should found on its applications the justification of her 

 existence. Like geometry, like all positive and speculative 

 knowledge, like fine art, even the science of the stars aims 

 especially at the honour of the human mind, and, from this 

 point of view, the discovery of Neptune is worth as much as 

 the discover)" of a new salutary remedy or of a new electrical 

 engine. On the other hand, the positions of the stars and 

 planets are now known and calculated with a precision far 

 superior to that which suffice for the applications. An imme- 

 diate accord like that of Paris seems thus superfluous for applied 

 astronomy and premature for pure astronomy. In any way, I 

 agree with Messrs. Boss and Chandler in the view that if an 

 agreement is to be come to, it is not in the form in which it was 

 given at Paris. American astronomers justly note that the 

 bureaucratic governmental character of the four offices publish- 

 ing the ephemerides is not a sufficient title for them to represent 

 all official and private astronomical science of the different 

 countries in the definition of a merely scientific controversy of 

 such moment. The directors of the four ephemerides indis- 

 putably occupy an eminent position amongst their colleagues ; 

 but, whatever may be their personal merits, their opinion (in a 

 matter that touches the foundations of science) is not such as to 

 impress itself authoritatively and without discussion. 



Moreover, I allow myself to add that such an opinion cannot 

 bind that of the numerous astronomers that belong to countries 



NO. 1467, VOL. 57] 



where ephemerides are not published, and where they are com- 

 piled (as at Trieste and at San Fernando) second-hand. The 

 resolution adopted by the organisers of the Conference of inviting 

 Messrs. Gill and Backlund, with a deliberative vote, Messrs. Van 

 de Sande Bakhuyzen and Trepied with a consultative vote, does 

 not seem to me to represent anything more than a well-deserved 

 homage rendered to those learned astronomers, and perhaps 

 might contribute to render more significant the exclusion of 

 other countries, such as Austria- Hungary, Italy, Sweden, 

 Norway, Denmark, the Argentine Republic, whose astronomers 

 till now have strongly and efficaciously contributed to the 

 theoretical and practical study of the arguments. As to what 

 refers specially to my own country, it may not be inopportune to 

 recall to mind the ancient series of ephemerides published, first 

 at Bologna, afterwards at Milan, which was interrupted twenty-five 

 years ago in order not to lose time and money by repeating what 

 was abundantly done at Paris, Berlin, London and Washington. 

 The history of the Milan Observatory in this last quarter of the 

 century, proves that the promises made by its director Schia- 

 parelli were not vain, that thus the Observatory might "dedi- 

 cate itself with greater alacrity to those researches that con- 

 stitute the real progress of science " (consacrarsicon maggiore 

 alacrita a quelle ricerche, che costituiscono il vera progresso 

 nelle scienze). 



Finally, I believe that the discussion on the conclusions and 

 aims of the Paris Conference should be continued by corre- 

 spondence in scientific periodicals, as well as by direct treaty 

 between the more competent bodies. And, perhaps, it would 

 not be without some utility were the Royal Astronomical Society 

 and the Astrottomische Gesellschaft to .agree to examine and 

 extend the plan devised some few years since by Dr. Gill for an 

 international Congress of Astronomers, by which alone the de- 

 liberations of the Conference could have full and authoritative 

 sanction. Fr. Porro. 



P.S. — The present paper was already finished when I read, in 

 No. 413 of the Astronomical Journal, Prof. Newcomb's reply to 

 the criticism of Prof. Boss. Notwithstanding the reasons 

 strenuously advanced by the learned astronomer of Washington 

 in support of his proposal of a new value for precession, it does 

 not seem doubtful that the question must be considered from a 

 wider and more general point of view. No one contests the 

 delicacy and the rigour of the procedure adopted by Newcomb 

 in drawing out his precession : no one denies but that he has 

 treated the difficult argument in a masterly manner, enlightening 

 it with his original and profound views. Where it seems to me 

 that Boss dissents from Newcomb is in the opportunity of expend- 

 ing such talent and labour about a material already exhausted 

 and not susceptible of giving more sure results, in whatever way 

 it be treated. In any way, even accepting the Newcomb's new 

 contribution to the study of the particular question of precession 

 with the praise due to it, the general question still remains open. 

 — Fr. p. 



The Treatment of Stamp Battery Slimes from 

 Gold Ores. 



On page 501 of your issue of September 23, there is given a 

 brief abstract of a paper read by myself at the July meeting of 

 the Chemical and Metallurgical Society of South Africa. 



The essential features of the paper have hardly been correctly 

 rendered in the condensation, inasmuch as at present mechanical 

 stirrers are employed for agitation of slime-pulp, jets of air 

 serving merely for oxidation, though their use as a means of 

 agitation is suggested. 



The primary use of aeration is described in the paper as the 

 oxidation of FeS, FeOj, H,, and other reducers, so as to effect 

 a preliminary preparation of pulp before adding cyanide ; hence 

 the KCy is not protected by the presence of FeS, which, with 

 other ferrous compounds, has already undergone oxidation and 

 become converted to ferric hydrate, in which state it neither 

 consumes cyanide nor abstracts oxygen. 



The COj in the air blown through the pulp is neutralised by 

 the free alkali (CaOjHj) present, which thus serves to protect 

 the KCy from decomposition. W. A. Caldecott. 



Johannesburg, November 8. 



Abnormal Colours of Flowers. 

 With reference to your correspondent's communication in 

 Nature for December 2, on abnormal colours of flowers, I 

 fancy the following note may be of interest. Towards the end of 



