Corrections in the Address of the President of the Royal Microscopical Society (Vol. xiii. p. 332)

Abstract

By some unaccountable oversight in copying out the data for calculating the number of molecules of liquid water, the factor expressing the specific gravity of the vapour of water was omitted, and afterwards overlooked. The number of atoms of a gas should really be multiplied by 3/2 × 770 × 1/.6239 × 1/3 = 617. But moreover, on reflecting on the relative reliability of the determinations by the various authors of the number of the atoms in gases, it appears that in taking the mean, greater weight ought to be allowed to that by Clerk-Maxwell, since founded on more recent and accurate data. If his results be considered as of equal value to those of Storey and Thomson combined, the mean, would be reduced to so nearly the same extent as the molecules of liquid water would be increased by the above-named correction, that the numbers given in the address may be considered to be as good an approximation to the truth as can be determined in the present state of the question, and none of the general conclusions need be modified.