of matter, begins to call for our attention, and to obtrude itself as a crucial factor in the case.
Clerk Maxwell dealt with this matter in his article ãAtom44,ã and, in somewhat greater detail, Errera discusses the question on the following lines45. The weight of a hydrogen molecule is, according to the physical chemists, somewhere about 8ôñ6ã₤ûã₤2ã₤ûã₤10ÿ£¢ã22 milligrammes; and that of any other element, whose molecular weight is M, is given by the equation
Accordingly, the weight of the atom of sulphur may be taken as
The analysis of ordinary bacteria shews them to consist46 of about 85% of water, and 15% of solids; while the solid residue of vegetable protoplasm contains about one part in a thousand of sulphur. We may assume, therefore, that the living protoplasm contains about
parts of sulphur, taking the total weight as =ã₤1.
But our little micrococcus, of 0ôñ15 ôç in diameter, would, if it were spherical, have a volume of