Dr Boss stated that he hoped to publish the first two volumes of the General Catalogue by the middle of the next year and the complete catalogue of four volumes by the end of 1936. A 5th volume containing the introduction will be published later.

Dr Jackson reported that Prof. Kopff would postpone the choice of the 3000 fundamental stars for photography till after the publication of Boss’s G.C.

Dr Gerasimoviç reported that the fundamental stars of magnitudes 7m.5—8m.5 which have been selected by Dneprovski for observation at Pulkovo and Nikolayev were stars of the M giant type.

La Commission s’est réunie le lundi 15 juillet, et a tenu deux séances. La pre mière, le matin, de 10 heures à 11 h. ½ à la Maison de la Chimie; la seconde, à 21 heures, à l’Amphithéâtre de Physique, à la Sorbonne, conjointement avec la séance mensuelle des Réunions de l’Institut d’Optique.

A. Matériaux. Le Président rappelle à l’attention de la Commission, la question de l’aluminure des miroirs, et résume les principaux avantages que cette nouvelle technique va procurer à l’astronomie physique. Il semble bien que l’argenture des miroirs de verre ait vécue. D’autres supports que le verre peuvent maintenant être avantageusement employés, en particulier les métaux susceptibles d’un beau poli, mais dont le pouvoir réflecteur est trop faible. Par l’aluminure, on retrouvera le haut pouvoir réflecteur des surfaces fraîchement argentées, avec l’avantage d’une très grande stabilité et l’absence de transparence dans l’ultra-violet.

The President referred to a proposal by Dr Royds, given in the Draft Report, and supported in a letter by Dr Nicholson; after a short deliberation, on which the President and several members (D’Azambuja, da Costa Lobo, Butler, Evershed, Rodés) expressed their views, it was unanimously decided that, in order not to break the existing records, the present scale 0-5 should be retained limiting the interpolation to a half unit.

Le Président évoque la mémoire du Dr C. E. Saint John, décédé peu de temps avant le Congrès et qui, alors qu’il présidait la Commission groupant toutes les recherches de Physique solaire, portait un intérêt très vif aux travaux dont s’occupe maintenant la Commission n.

Deux demandes de subventions ont été soumises à la Commission: l’une, de M. le Prof. G. Abetti, pour continuer la publication des Immagini spettroscopiche del bordo solare; l’autre, de M. E. Esclangon, pour poursuivre celle des Cartes synoptiques de la chromosphère établies à Meudon. Les demandes de subventions sont approuvées par la Commission.

The Chairman referred with sorrow to the loss of Dr St John, the former President of the Commission, who died a few months before the meeting.

Solar radiation. The President suggested and Prof. Chapman agreed that it would be interesting to make investigations at high altitudes, especially at wave-lengths of about 2100 A.

Solar Spectroscopy. Prof. Russell said that the publication of new tables of the infra red solar spectrum would be delayed by the illnesses of Miss Moore and of Dr Babcock.

At the request of the President, Prof. Sotome gave some information about the possibilities of observing in Japan and offered to give any additional details to all those who were interested. In the best central part there was about 40% probability of a clear sky.

No Russian astronomer being present, Prof. Carroll reported that scientific workers in Russia were anxious to give all possible cooperation; he intended to go himself to Russia this summer, in order to prepare an expedition to Siberia, and he was prepared to get all questions answered which any one should wish to put. Letters about this subject must reach him before the end of August.

Prof. Fowler expressed regret at the absence of Messrs Babcock, Burns, Kayser and Nagaoka.

In opening the discussion on sources of the primary standard, Prof. Fowler presented the following extracts from a communication which had been forwarded by Mr Babcock:

“The preliminary specifications adopted by the I.A.U. in 1925 are a simplified description of the Michelson lamp, naming the conditions which were at that time considered necessary and sufficient by Prof. Fabry himself. Even by implication they do not suggest a substitute for the original lamp. It goes without saying that a vacuum tube provided with internal electrodes is not intended for use with high frequency, but rather with the customary well-known type of excitation. In any case, before amending our specifications so as to prohibit high frequency excitation, at least three laboratories should agree that this is necessary.”

The President referred to two matters left over from the meeting at Cambridge, Mass, in 1932, viz. (a) the formation of a small sub-committee on Martian Nomenclature, and (b) the appointment of a Secretary to deal with the work on the physical study of comets. He had requested Messrs Antoniadi, Lampland, and Maggini to form the Committee on Martian Nomenclature, but the question was difficult and complicated, and it had not yet been found possible to come to a conclusion apart from the acceptance of the nomenclature of Schiaparelli as an agreed basis.

The President reported that the work of the Commission had been achieved and two volumes published and distributed. These are: (1) a volume of named lunar formations and (2) a volume of 14 maps with corresponding names upon them.

After some discussion it was proposed to recommend that the Commission should be continued on a broader basis and called “La Lune”—but divided into three sub-commissions.

1. (1) Visual and Photographic Observations of the Surface.

2. (2) Physical Observations.

3. (3) Mathematical researches and occultations.

Après lecture du rapport par le Président, celui-ci met en discussion les questions à l’ordre du jour:

1. Centralisation au B.I.H. des résultats obtenus au cours de l’opération de 1933 par toutes les stations participantes.

Le Président fait connaître que 55 stations seulement ont déjà fait parvenir les renseignements demandés. Il demande que les autres stations veuillent bien communiquer leurs documents le plus rapidement possible.

Dans l’absence de M. Kimura, Président de la Commission, et de son remplaçant, M. Schlesinger, Président de l’Union, prit le fauteuil de présidence.

Il constata qu’il était maintenant nécessaire de considérer la question de transférer le siège du Bureau Central à cause de la mauvaise santé de M. Kimura. M. Tanakadate dit que le gouvernement japonais était prêt de continuer les subventions actuelles pour un an de plus, si l’Union le désirait.

I. ‘Joint meeting of Commissions 6 and 20 on Thursday morning, July 11.

The cipher code for astronomical telegrams (relating to the description of objects and other matters) proposed by the President of Commission 6 (Prof. Strömgren) was discussed and accepted, with minor alterations. (See report Of meeting of Commission 6, page 289; also the cipher code adopted, page 391.)

2. Joint meeting of Commissions 4, 8 and 20 on Thursday afternoon, July 11. (See also reports of meetings of Commissions 4 and 8, pages 281 and 290.)

The proposals of Noumerov (Leningrad) and Brouwer for the determination of systematic corrections to star positions from observations of minor planets were discussed, and the following resolution passed for action by the General Assembly. “Commissions 4, 8 and 20 recommend that the programme of M. Noumerov for the determination of systematic corrections to star positions from observations of minor planets and the similar programme advanced by Mr Brouwer be encouraged as being of great importance, but that the formation of a subcommittee of one of the existing commissions or of an independent commission for the co-ordination of the two programmes and the promotion of international co-operation of observatories and planet institutes or almanac offices be deferred pending the outcome of the experimental stages of the two programmes.”

The Commission first took up the question of the inclusion in their subjects of the Zodiacal Light and related phenomena, and in particular the brightness of the night sky, which had been referred to them by the General Assembly. After some discussion, the following resolution, proposed by the acting President, and seconded by Dr Bosler, was adopted: 1. While, in conformity with the motion voted by them at the Harvard Meeting (Transactions, 4, p. 245), this Commission still consider that it is not desirable that Comets should be added to their subjects, they suggest that, since several of theirmembers, active in the field of meteors, are also working on the problem of Zodiacal Light, the latter subject, and related phenomena, might be handled by a Sub-Committee of Commission 22.

M. le Président rend hommage à ceux de ses membres que la Commission a perdus depuis sa précédente réunion: son vénérable et eminent Président d’honneur Benjamin Baillaud, premier Président de l’Union; et Monsieur Gonnessiat qui fut Directeur de l’Observatoire d’Alger.

Il souhaite la bienvenue aux membres nouveaux: MM. Donner, Furuhjelm, Nangle, Paloque, H. H. Plaskett, Stein.

Il expose l’état d’avancement du Catalogue et de la Carte, fait ressortir que, malgré les progrès réalisés depuis la réunion de Cambridge, il reste encore beaucoup à faire et insiste sur l’importance qui s’attache à l’achèvement des travaux dans les délais les plus réduits.

The Commission held two sessions. At the first session there was an interesting discussion in which the majority of the eighteen members of the Commission present participated.

The second session was given over to stellar parallaxes. Dr Adams described the methods followed at Mt Wilson in deriving the spectroscopic parallaxes of 4179 stars and Dr Schlesinger explained the methods for deriving the values given in the Second Yale Catalogue. Parallax programmes were discussed by various observers.

The acting chairman read a letter from the President of the Commission, Mr F. H. Seares, calling the attention of the Commission to certain points of importance which might be taken up for discussion. In the course of this discussion Dr H. Shapley invited cooperation with the Harvard Observatory on the work of unification of the magnitude systems in the northern and southern sky.

After a discussion on the problems of standardizing colour filters and photographic plates used in stellar photometry the recommendation suggested by Dr Shapley that all engaged in photometric research publish promptly the characteristics of their instruments, colour filters, etc., was adopted.

The President read the draft report. No objections being entered, this was adopted by the meeting.

The President proposed an addition to the report. This was agreed to.

The adoption of a single system of orbital elements was advocated by van den Bos, who reported on the correspondence which had taken place on this subject with the members. As the result of all answers received, a system of elements was proposed and adopted by the Committee.

The President suggested that this be given in the report and van den Bos, at the request of van Biesbroeck, proposed that a full set of definitions and formulae be added. This was agreed to.

The draft report was discussed, and adopted with some alterations and additions. The following resolutions were referred to the General Assembly:

1. 1. The Commission recommends that the yearly subsidy granted by the Union for the publication of the Cracow Ephemerides of Eclipsing Binaries (Prof. T. Banachiewicz) be continued to the amount of 700 gold francs, and expresses the wish that the decimal division of the day used in these ephemerides will be, in the future, counted from Greenwich Noon.

2. 2. The Union having endorsed the proposal made by Prof. Grouiller to compile a list of unpublished observations of Variable Stars, and recommended that this compilation be published by the Union, the Commission recommends that a subsidy of 200 gold francs should be granted to that object.

3. 3. The Commission recommends that Prof. Nijland’s Lists A, B, and C, brought up to date, together with a new list D, should be published by the Union with a subsidy not exceeding 300 gold francs.

Except for a brief discussion of the zero point of the period-luminosity curve and the influence of the absorption of light on its determination, the discussions were mainly confined to the draft report which was approved by the commission. The President read a report from Dr Lampland, which had not been included in the draft report and Prof. Lundmark gave an account of his work on extragalactic nebulae, in particular of the catalogue of about 50,000 nebulae which is now being prepared at Lund.

The President drew special attention to the importance of the problem of the spiral arms for future cosmogonie theories and urged further theoretical investigations on the origin of the spiral structures.

1. Le rapport distribué aux personnes présentes commence par un court aperçu des principaux travaux faits dans le domaine des spectres stellaires depuis l’assemblée précédente. Le Président demande si l’une ou l’autre personne désire suggérer des modifications ou compléments à cet exposé. Aucune observation n’est présentée.

2. Le rapport du sous-comité chargé de l’examen des critères de classification des spectres stellaires est ensuite mis en discussion. Une lettre de Mme Payne-Gaposchkin a été reçue à ce sujet; Mme Payne-Gaposchkin signale que des détails manquent dans le rapport du sous-comité; elle demande aussi que soient définis clairement les types A7 et K7 actuellement utilisés fréquemment, ainsi que les symboles g et d distinguant les étoiles géantes et naines.