THE ROYAL SOCIETY OF VICTORIA. 359 



In my last address I told yon tliat the Great Sontliern Telescope, wliicli, by- 

 tlie-bv, is now to be styled the Great 2lclhounie Telescope^ was ap[)roacliiu£;- com- 

 pletion, and its arrival miglit be expected in the course of a few months. It has, 

 however, not yet reached us. Several ludookcd for delays in its construction 

 occurred, principally owinij' to the determination on tlic part of the manufacturer, 

 Mr. Grubl), that nothing but the very highest excellence in all its parts should 

 go to its construction. 



Many of you, no doubt, read the interesting letter of Dr. Robinson, of Armagh, 

 ■which appeared in the daily papers a week ortwo since, respecting his inspection 

 and trial of this great instrument, and that he passes a high eulogium on the 

 excellence (»f its mechanical details, as well as of its optical powers, so far as he 

 was enabled to judge from the impei'fect trial he had with it in this respect. We 

 are expecting every mail to hear of its shijiment, and there appears to be every 

 probability of its being even now on its way. M. Lc Sueur, a gentleman selected by 

 the conunittee as an ot)server for this telescope, comes out with it, and will occupy 

 the position of second assistant astronomer at the observatory. Of this gentle- 

 nuin's high qualifications for the work before him we have the best testimony. 

 You are aware, no doul)t, that ap])aratus for celestial photography and spectrum 

 analysis of the light of the heavenly bodies will form part of the appliances of 

 thisgiganticinstriunent,and I trust that Dr. liobinson's hope '' that an inestimable 

 harvest of discovery and triumph will crown this magnificent enterprise " will be 

 fully realized. I have obtained a few photographs of a lithograph of the Great 

 Melbourne Telescope, which will be handed to you at the conclusion of thia 

 address. 



It .appears that some kind of a building with movable roof will bo necessary 

 to protect it from the great damage likely to arise if exposed to the dust-storma 

 we are liable to ; it is therefore proposed to erect a circular building, with a 

 revolving roof, and Parliament will be asked for a vote for this purpose. A 

 small extension of the observatory ground has been granted, thus enabling the 

 telescope Ut be erected in a position where it will command a full view of the 

 Leavens without creating any disturbance on our magnetic instruments by its 

 too close j)roximity. 



You will remember that in my last address I mentioned that a complete set of 

 self-registering magnetic instrumenlsor magnetograjdis (similar to those used at; 

 Kew) were expected to arrive shortly. These duly arrived ; they have been 

 erected and at work since November last, producing an uninterrupted photographic 

 record of all changes of the forces of terrestrial magnetism. 



A wet and dry bull> thermometer and barometer, continuously self-registering, 

 on the same principle, are now being constructed for us, and will probably beat 

 work in the course of a few months. The results likely to be obtained from the 

 adoption of self-registering instrument*^ of this kind can scarcely be too highly 

 estimated, for the periodic method of observing phenomena that are changing 

 continuously could never satisfactorily admit of those close deductions being made 

 requisite to derive any practical value from the observations. Variations of the 

 forces measm-ed suflicient to establish or overthrow a supposed law may, and 

 doubtless do, often hapjien in tlie intervals between intermittent observation, 

 which, by the plmtographic or other self-registering method, is indelibly recorded 

 with true; relations to preceding and following variations. 



The Melbourne portion of the survey of the southern heavens has made con- 

 siderable progress ; the ))ortion of the heavens lying between the JoO" 40' and 

 l;Kd° ■!(/ parallels of declination have been thoroughly siuveyed, and the i)osi- 

 tioiis of 19,000 stars established. 



A scries of observations for the determination of the difierenco of longitude 

 between iMelliourne and Adelaide, by aid of the electric telegraph, was made at 

 the latter part of last year, and although the result is considered not (piite conclusive, 

 as it is intended to make anotherseries ofcomparisons, itmay however be accepted 



