The following communication was read : 



"On what the Colonial Magnetic Observatories have accom- 

 plished." By Major-General SABINE, R.A., Treas. and 

 V.P.R.S. Received February 26, 1857. 



It has been suggested to me, that a brief review of what has been 

 accomplished by the Colonial Magnetic Observatories, instituted on 

 the joint recommendation of the Royal Society and British Associa- 

 tion, would be acceptable ; and that the officer who has been en- 

 trusted with the superintendence of these establishments is the person 

 from whom such a review may most properly be expected. Fully 

 assenting to both propositions, I have readily undertaken the task ; 

 and have availed myself of the occasion to add a few remarks and 

 suggestions on the measures which appear to be required for the 

 further prosecution of the objects for which the observatories were 

 recommended. 



The magnetic investigations designed to be carried into execution 

 by the Colonial Observatories recommended by the Royal Society 

 embraced a much wider scope than had been contemplated by any 

 previous institutions, or than had been provided for by the arrange- 

 ments or instrumental means of any then existing establishment, 

 whether national or private. Not, as previously, limited to obser- 

 vations of a single element (the Declination), or combining at the 

 most one only of the components of the magnetic force, the in- 

 structions of the Royal Society, and the instrumental means prepared 

 under its direction, provided for the examination, in every branch of 

 detail, of each of the three elements which, taken in combination, 

 represent, not partially but completely, the whole of the magnetic 

 affections experienced at the surface of the globe, classed under the 

 several heads of absolute values, secular changes, and variations 

 either periodical or occasional, and proceeding from causes either 

 internal or external. To meet the requirements of inductive reason- 

 ing, it was needful that the results to be obtained should comprehend 

 all particulars under these several heads, attainable by an experi- 

 mental inquiry of limited duration. That no uncertainty might 

 exist as to the objects to which, in so novel an undertaking, attention 



