r6o 



NATURE 



[March 30, 191 1 



THE DOMINION OHSEKVATOKY, CANADA. 

 ,pUK annual nports issued by Dr. King, the chief 



I astronomer, dealin|< with the work performed at, and 

 by, the Dominion Observatory, are comprehensive voiumeK 

 worthy of a place on the library shelves of every observa- 

 tory for the purpose of general reference. 



The organisation of a modern astronomical institution 

 is no mean task, and to have the experiments, failures, 

 and successes so clearly set forth as they arc in these 

 volumes, for the work is still in progress, is to be counted 

 as one of the important achievements of the Canadian 

 astronomers. 



Perhaps the most striking feature of the organisation 

 of astronomical labours in Canada is the manner in which 

 collateral and interdep«'ndent researches are brought under 

 the same direction. Dr. King's directorship includes 



Observing Tower, 87 feet high, near Howesville. 



seismology, terrestrial magnetism and gravity, astro- 

 physics, meridian work and time service, longitude and 

 latitude observations, spectroscopy and solar phvsics, with 

 all their subdivisions and ramifications. Such organisa- 

 tion makes for a great saving of time and correspondence • 

 records of one branch are readily available, on the spot, 

 for correlation with those of other branches, and auxiliary 

 researches, such as can be more readily prosecuted in 

 divisions other than that in which the results are actually 

 required, can be readily ordered by the same direction. 

 Unfortunately in this country we, at present, lack such 

 a properly organised institution, although in other coun- 

 found^ ^PP<>''tun'ty and money to instal them have been 



The report published in 1910 deals with the work done 

 auring the year ending March 31, 1908, and, in 3^6 pages, 

 ujcludes seven divisional reports, not merely of the work 

 attempted but the actual results in each division. A few 

 onjy of the more striking features may be summarised 



NO. 2 161, VOL. 861 



Dr. Klotz is responiiible ior the geophysical departm<nt. 

 and he diturusses very thoroughly the working and in 

 ment of the seismographs, &c., and enters into a ; 

 discussion of the results. Regarding the sug;^ 

 the boom acts as a delicate barometer, re^^ 



tilting produced by excess or defect of .a. 



pressure, he, as yet, preserves an open mind, al: 

 the preliminary discussion of the results, given in • 

 in the report, indicates a connection between the presence 

 of a " low " over the Gulf of St. i.awrence and the 

 incidence of well-marked microseisms at Ottawa later in 

 the same day. Rut there are important outstanding differ- 

 ences which call for further investigations. 



The magnetic elements, and their variations, are also 

 recorded in full, and the isogonic lines for 1907 are shuwn 

 on an excellent large map of Canada accompanyi; 

 report. 



Mr. Plaskett contributes a voluminous and important 

 report on the astrophysical work (pp. 65-273), in which a 

 prominent feature is the investigation of spectro : 

 binaries. Those conversant with Mr. Plaskett 's pu 

 papers will readily understand that a great deal of 

 tical information concerning the apparatus and methods 

 employed makes his report both interesting and useful for 

 reference to tnose engaged in similar researches. For 

 each star dealt with practically every possible datum is 

 recorded, and the results are carefully summarised and 

 discussed. 



Five appendices to Mr. Plaskett *s report deal with 

 special researches coming under the head of astrophysics. 

 Of these Mr. Harper contributes two, dealing, respectively, 

 with the orbits of the spectroscopic binaries »; Virginis 

 and e Aquihx. Mr. Motherwell discusses the measurement 

 of visually double stars. Dr. De Lury gives an account of 

 the determination of the wave-lengths in the spark spec- 

 trum of iron-vanadium alloy between W 3900 and 4900, 

 and Mr. Tobey discusses the photometric observations. 



For solar work, the observatory is equipped with a 

 23-foot plane-grating spectroscope, used with a coelostat 

 and photographs of the sun, 7J inches to the solar disc, 

 are taken on even,- clear day, but during the period 

 covered by the report the solar work was delayed by 

 difficulties in getting the necessary buildings completed. 



Mr. Stewart's report on the meridian work and time 

 service also contains many practical hints useful to those 

 engaged in similar work. The observatory controls a 

 number of synchronised public clocks, and the methods of 

 synchronisation are carefully described. Difficulties with 

 the various piers, which cracked under the influence of 

 frost, interfered with the meridian work to some extent, 

 but the account of them affords instructive reading. The 

 primary azimuth-marks are now installed underground, as 

 at the Cape Observatory. 



It is interesting to note here the great advantages 

 secured by having a properly equipped workshop attached 

 to the observatory, an institution without which any 

 observatory where a number of instruments are employed 

 in experimental researches is sadly handicapped. At 

 Ottawa— as at Mount Wilson, Mount Hamilton, and many 

 other important observatories — apparatus can be made, or 

 modified, and adapted under the actual supervision of the 

 observer who wishes to use it ; and a great deal of time, 

 trouble, and expense often required to instruct the some- 

 times unadaptable outside mechanician is thereby saved. 

 \yhile there is some satisfaction in constructing an effective 

 piece of apparatus from odd pieces of wood and metal, 

 with the aid of a penknife, the results attained are not, 

 inevitably, always the most satisfactory attainable for the 

 purpose. 



The results of the latitude and longitude observations. 



1907, are tabulated by Mr. Macara in .\ppendix 4. and 

 the astronomical stations established up to March 31, 



1908, are shown on a large-scale map of the Dominion 

 which accompanies the report. Appendix 6 is a summary 

 of the photographic work, and in the next section Dr. 

 King reprints his paper, from The Astrophysical Journal, 

 on the determination of the orbits of spectroscopic binaries. 



The geodetic work, whilst primarily utilitarian in 

 character, aspires to take its place among the " great " 

 surveys — for the determin.ition of the earth's figure — and, 

 judging from the results given in Mr. Bigger's most 

 interesting report, it will not be found wanting in pre- 



