“If we call M the mass of a body, and V its apparent volume, the fraction M/V is the absolute density of the body. The absolute density is, therefore, unity for an atom, and varies from 0 to 1 for all bodies.”
If two bodies have the same apparent volume, their densities are proportional to their masses.
I have been looking through a capital French work on Chemistry, published in 1870, by M. Alfred Riche, lecturer at the Polytechnic School at Paris. He uses the old notation and table of equivalents; but strongly advises a change to the new, which he explains very nicely, and pretty much as our lecturer has done. Whenever the atomic weight of an element is given according to the new table its symbol has a bar drawn across it. Something of this sort should always be observed, in order to avoid confusion between the old and new formulæ.
I have just received a letter from Mr. J. R. Johnson, containing a most beautiful carbon print. He asks me what I think of it. My reply is simply this—that it is the most wonderfully fine print I have ever seen upon paper.
Thomas Sutton, B.A.
Redon, January 26, 1872.
The Recent Solar Eclipse.—New Photographic Venture at the Antipodes.—Photography in the Bush.
The most interesting event, in a photographic point of view, which I have to report is the departure of the scientific expedition to observe the total eclipse of the sun on the 12th of this month. The place selected for the observations is Cape Sidmouth, some three hundred miles south of Cape York, in Northern Australia.
The expedition has been organised by the Royal Society of Victoria, and the expense is met by private subscriptions, largely aided by grants from the several Colonial Governments. The Queensland Government steamer was also placed at the disposal of the party free of charge.