inch. The results already obtained are very promising, though its situation near the traffic of the adjoining street exposes the instrument to considerable disturbance. Sun Photographs.-Daily photographs (glass negatives) of the Sun's disc are received from Dehra Dun (India) and from Mauritius, the gaps in the Indian record being filled up as far as possible by negatives from Mauritius and Greenwich. The negatives are forwarded to Greenwich for measurement and reduction as they are required. Positives on paper are also received. These are mounted on cartridge paper and bound up into half-yearly volumes for ready reference. Since the beginning of 1906 enlargements of spectroheliograms for the same dates have been mounted alongside the paper prints for comparison. Spectroheliograph.-The weather conditions were distinctly less satisfactory for the purposes of this instrument than during 1906, though fine enough on 142 days to warrant attempts being made to obtain monochromatic photographs of the Sun in “K” light. The instrument cannot be used very satisfactorily during the winter months on account of its position among high buildings. During the period January 3 to December 13, 1907, 351 negatives were secured, showing the distribution of "K" radiation on the Sun's disc. With the addition of an occulting disc over the primary slit plate 62 negatives were obtained, showing the prominences round the solar limb. By arrangement with the Indian Government, photographs taken with the spectroheliograph at South Kensington and Kodaikanal are exchanged, so that the records may be as complete as possible for the year. During the period January 1, 1906, to September 30, 1907, 465 spectroheliograms have been received from Kodaikanal, while during the years 1906 and 1907, III positives, showing the Sun's limb in "K" light, have been forwarded to Kodaikȧual. The measurement of the spectroheliograms is now proceeding. Though, for many reasons, the work is extremely difficult, the consistency of the results, so far obtained, has been very satisfactory. Stellar Spectra.-The weather conditions for night observations have been less favourable than during 1906. Fifty-two photographs of fifteen stellar spectra have been obtained with the 6-inch Henry prismatic camera with two prisms, and eight stellar spectra with the 9-inch prismatic reflector. The 2-inch quartz-calcite prismatic camera has been employed in photographing twenty pairs of stellar spectra, under conditions as nearly constant as possible, for recording extensions of the spectra in relation to the positions of the stars on the temperature curve of the Kensington classification. The weather has been extremely unfavourable for the photography of faint objects with the 36-inch reflector. Experimental work with plates specially sensitised for the green region showed a satisfactory advance. Among other photographs, a good spectrum, in the green region, of the Orion nebula was obtained. Publications.-Papers dealing with the pressure data of 73 selected stations over the Earth's surface, the report of the eclipse expedition to Palma, Majorca, August 1905, the presence of sulphur in some of the hotter stars, the spectroscopic comparison of metals present in certain celestial and terrestrial light sources, observations of Sun and stars made in some British stone circles, prominence and coronal structure, and a note on the permanency of some photo-visual lenses, have been completed during the year, and others on allied subjects are in course of preparation. Royal College of Science, South Kensington. Observations of the spectra of sun-spots have been continued in accordance with the scheme of the International Union for Solar Research. The spectra of the umbræ showed no perceptible differences as compared with those recorded in the preceding year, and dark D, was very frequently observed in the circumpenumbral regions. Solar prominences were also observed when time permitted, and particular attention was given to the bright lines visible in metallic eruptions. Further investigations of terrestrial spectra have been made, with special reference to the interpretation of solar and stellar phenomena. A detailed account and table of wave-lengths of the titanium oxide flutings, which are characteristic of the Antarian (third type) stars, has been published (Proc. Roy. Soc., vol. lxxix.a p. 509). An interesting result of the experimental work was the identification of the well-known sun-spot bauds between E and F, with the component lines of the flutings of "magnesium hydride,' a preliminary account of which was communicated to the Society in June. The continued investigation of this spectrum has shown that many other spot-bands in the yellow, green, and blue are also accounted for by magnesium hydride. Stonyhurst College Observatory. The solar surface has been observed as usual on all available days; 198 drawings of spots and faculæ have been made, and the greater spots have been examined with the grating spectrometer and the 12-prism spectroscope. The new heliostat, mentioned in our last report, and also a 6-inch portrait lens-the gift of Mr. Whitelow, F.R.A.S.-have been mounted, but regular work with both instruments has been delayed by impediments experienced in the running of the driving-clocks. Sir Howard Grubb is surmounting those of the heliostat; and the Director, with the friendly help of Mr. Parkinson, a mechanician of Blackburn, has so far improved the equatorial clock gear and the adjustments of the Whitelow camera that probably no further difficulty will be experienced in a long and repeated exposure of the same photographic plate. These and other mechanical improvements have occupied a considerable part of the year, and many of the clear nights have been devoted to experimental work in connection with them. Work with the stellar spectrographs has been practically discontinued, pending an examination of the collection of plates already made. But this examination has been rendered impossible during the past year by the very long and laborious work, now complete, of re-casting all the meteorological computations of the last sixty years. Some trials of Wratten and Wainwright's pan-chromatic plates on the brightest stars have been made with the Hilger compound prism. These carry the spectrum to Fraunhofer's C, and with them it is intended to complete the photographic records of the stronger spectra in our collection. Wolsingham Observatory (Rev. T. E. Espin's). Micrometrical measures of new pairs and neglected double stars have been continued throughout the year, and the results presented to the Society. Mr. Franklin-Adams' Astrographic Laboratory. In order to push on with the "Chart of the Heavens," all other work has been suspended and a second assistant engaged. Extra help has also occasionally been employed. At the turn of the year a week-end conference upon several matters in abeyance was held at Mervel Hill with Sir David Gill, Professor Kapteyn, and Mr. Eddington, in order to make the work as useful as possible in the investigations now being carried on by them. Messrs. Troughton & Simms have delivered the enumerating machine, and experimental investigations of numbers and magnitudes of stars upon the 15-inch plates are in hand. Preparations for publication are in hand, but the scarcity of nights with three hours' spells of brightness makes it impossible to foretell the date of commencement. A new workshop has been built for the production of 15-inch positives. Sir William Huggins' Observatory, Upper Tulse Hill. Photography of spectra, and experimental work in several directions, are being carried on in the observatory and in the laboratory. Sir Wilfred Peek's Observatory, Rousdon, Lyme Regis, Devon. (Mr. C. Grover, Observer in charge.) The observatory and instruments are in good working order. The very changeable and unsettled weather of 1907 has been a great hindrance to observations, which were only made on 136 nights; this is less than usual. August, September, and October were the three best months, with 47 fine nights. The observations of long-period Variable Stars have been continued with the 6'4-inch Merz equatorial refractor, and 368 magnitude determinations have been made. Argelander's method has been followed, as in the previous twenty-two years this work has been in progress, during which a total of 10,075 magnitude determinations have been recorded. Transits of stars are taken as often as required for regulation of the sidereal clock, which maintains a good steady rate. The planet Mars was observed on 15 nights, and 13 drawings of the disc were made between July 1 and August 9; the presentation of the disc was much the same as in 1892, when a fine series of drawings were made by Professor Keeler, which appear in vol. li. of the Memoirs R.A.S. Many of these well-known features were well seen at the recent opposition. Comet Daniel (d 1907) was observed on many nights between July 2 and August 21, at which latter date the comet was a fine naked-eye object with a tail 14° in length-the brightest comet which has been seen for several years. The disappearance of Saturn's ring was well seen. It was visible as a fine hair-line of light on either side of the planet on October 2, and the next night it had totally disappeared, no trace of it being seen with powers 80 to 310. On October 12 the air was so clear that six of the satellites were visible, but no trace of the ring. Mr. Saunder's Observatory, Crowthorne, Berks. The principal work has been in continuation of the measurement and reduction of the two Yerkes negatives of the Moon. The reductions of the plate dated 1901 November are completed, and the resulting places of 1800 points copied on to the card index. On that dated 1901 August about 800 points have now been completely measured and reduced; some 700 more are at present measured once only. Dr. W. E. Wilson's Observatory, Daramona, Co. Westmeath. During the last year practically nothing has been done with the 2-feet reflector. The weather still remains remarkably cloudy. Numerous experiments have been made with the radio-integrator, and that instrument now gives excellent results. Kodaikanal and Madras Observatories. (Acting Director, Mr. J. Evershed.) The first five months of the year were, as is usual at Kodaikanal, extremely favourable for solar observations. September and December were also favourable, but the remaining five months were unfavourable. Photoheliograms were taken on 339 days, and it was found possible to send to Greenwich all the negatives required to fill in the gaps in the Greenwich and Dehra Dûn sets of daily photographs. Spots were observed on 352 days, and their positions approximately determined by projection. A total of 301 new groups was recorded, and the mean daily number of groups visible varied from 27 in June to 7'1 in February, the average for the year being 46. Spectroscopic work.-Prominences were observed and their positions charted on 305 days. Detailed observations were also made of the bright lines in metallic prominences. Spot spectra were observed on 129 days, and a photographic investigation of the spectra of some of the larger spots of the year was successfully carried out, using a parabolic and a plane grating. Photographs were also obtained of the spectrum of Comet Daniel with a prismatic camera. Spectroheliograph.-After the completion of the new sliding roof covering the siderostat, work was started on February 1. In April a new primary slit was fitted, and the design of the secondary slit was considerably modified. It was also fitted with a device for automatically recording the setting after each exposure. The instrument has since worked quite satisfactorily, and in the eleven months from February 1 photographs of flocculi were taken on 300 days and of prominences on 253 days. Altogether, 1840 photographs were taken. Publications.-Bulletins Nos. viii. to xi. were published during the year. At Madras, astronomical observations were confined to those necessary for the time service. Perth Observatory, Western Australia. This year has been a memorable one for all the Australian State observatories, because it marks the definite separation of the two departments of Astronomy and Meteorology. Hitherto each observatory has had complete charge of the meteorological work of its State, but a Central Commonwealth Weather Bureau has now been established, and from 1908 January 1 each State Astronomer will be able to devote the whole of his time to Astronomy. At the Perth Observatory the year 1907 has been marked by considerable progress. All the Catalogue plates have now been |
