23 March 1871
In reference to the enclosed letter 71/1900 I have the honor to report as follows: In February last our?? surveyor Dearing wrote to me?? for certain information about the Magnetic variation at Sydney, and asked: “Is the variation moving westerly now”?
In reply to that letter of which a copy is enclosed I gave him the variations contained in his letter of March 4th, with permission to make use of them thinking such was necessary to complete his plans of?? the work then in hand.
I have since September last been investigating the past and present variation of the Magnet in Sydney. with the intention of making a full report on the ??ffect?? as soon as I had obtained the necessary dates; after much seeking in the past, records and histories of the Colony I have succeeded in bringing to light some valuable information and correcting several palpable errors in the variations given by different ??
As the result of the investigation so far I had some time since prepared a chart of the variations from 1798 to 1871 and so arranged it that at least the approximate variation for any year in that period might be obtained by inspection.
I now endorse a copy of the chart and must reserve to a future occasion certain
additional information which is not yet completed.
I have the honor to be
Sir Your Obedient Servant
The Principal Under Secretary