Ferdinand von Mueller

1

Letter not found. For the text given here, see Transactions of the Philosophical Institute of Victoria, vol. 4 (1860), p. 14, where the letter was published under the heading 'Some interesting facts founded on barometrical observations'. The letter was read before the Philosophical Institute on 30 March 1859 and was also published, without the accompanying graph, in the report of the meeting, Argus, 31 March 1859, p. 5.

Sydney, 15th Dec., 1858.

Dear Sir,

In the course of the investigations of the variations of the barometer which were necessary for the computation of the altitudes of the various portions of the interior traversed by the late expedition from Moreton Bay to South Australia, there appeared such a remarkable coincidence in the rise and fall of mercury at stations 500 to 1000 miles distant, that I constructed a diagram, exhibiting the comparative changes at Adelaide, Melbourne, Sydney, and Moreton Bay.

2

The text is accompanied by a large fold-out graph headed: 'Barometrical observations recorded at Adelaide, Melbourne, Paramatta & Cape Moreton. Shewing the comparative variations of atmospheric pressure. January to July 1858.'

Knowing the interest you take in all branches of science, I send you a copy of this diagram, as, if placed in the hands of some of your scientific friends who are engaged in meteorological investigations, it may suggest some more perfect and effective system of tracing the course of storms, &c. The reason for thinking that these investigations may be of practical importance is, that all great changes of atmospheric pressure appear to take place at the South-Western stations many hours earlier than at the North-Eastern ones — thus Adelaide precedes Sydney by 12 to 24 hours, and it is not impossible that, with the rapidly extending system of electric telegraphs, timely notice of approaching storms may be transmitted from one seaport to another.

To Dr. Ferdinand Mueller,

President of the Philosophical Institute of Victoria.