hen Professor William Thomson developed in so
striking a manner the meteoric theory of the sun's heat, he was
certainly not aware of the existence of that essay, though from a
recent article in 'Macmillan's Magazine' I infer that he is now aware
of it. Mayer's physiological writings have been referred to by
physiologists--by Dr. Carpenter, for example--in terms of honouring
recognition. We have hitherto, indeed, obtained fragmentary glimpses
of the man, partly from physicists and partly from physiologists; but
his total merit has never yet been recognised as it assuredly would
have been had he chosen a happier mode of publication. I do not think
a greater disservice could be done to a man of science, than to
overstate his claims: such overstatement is sure to recoil to the
disadvantage of him in whose interest it is made. But when Mayer's
opportunities, achievements, and fate are taken into account, I do not
think that I shall be deeply blamed for attempting to place him in
that honourable position, which I believe to be his due.

Here, however, are the titles of Mayer's papers, the perusal of which
will correct any error of judgment into which I may have fallen
regarding their author. 'Bemerkungen ueber die Kraefte der unbelebten
Natur,' Liebig's 'Annalen,' 1842, Vol. 42, p. 231; 'Die Organische
Bewegung in ihrem Zusammenhange mit dem Stoffwechsel,' Heilbronn,
1845; 'Beitraege zur Dynamik des Himmels,' Heilbronn, 1848;
'Bemerkungen ueber das Mechanische Equivalent der Waerme,' Heilbronn,
1851.

====================

IN MEMORIAM.--Dr. Julius Robert Mayer died at Heilbronn on March 20,
1878, aged 63 years. It gives me pleasure to reflect that the great
positionwhich he will for ever occupy in the annals of science was
first virtually assigned to him in the foregoing discourse. He was
subsequently hosen by acclamation a member of the French Academy of
Sciences; and he received from the Royal Society the Copley medal-its
Highest reward. [Footnote: See 'The Copley Medalist for 1871,' p.479.]

====================

November 1878.

At the meeting of the British Association at Glasgow in 1876--that is
to say, more than fourteen years after its delivery and
publication--the foregoing lecture was made the cloak for an unseemly
personal attack by Professor Tait. The anger which found this
uncourteous vent dates from 1863, when it fell to my lot to maintain,
in opposition to him and a more eminent colleague, the po