Elements which are similar as regards their chemical properties have atomic weights which are either of nearly the same value (eg. Pt, Ir, Os) or which increase regularly (eg. K, Ru, Cs).

Knowing how contented, free, and joyful is life in the world of science, one fervently wishes that many would enter its portals.

The elements, if arranged according to their atomic weights, exhibit an apparent periodicity of properties.

It is the function of science to discover the existence of a general reign of order in nature and to find the causes governing this order. And this refers in equal measure to the relations of man - social and political - and to the entire universe as a whole.

There exists everywhere a medium in things, determined by equilibrium.

No law of nature, however general, has been established all at once; its recognition has always been preceded by many presentiments.

The edifice of science not only requires material, but also a plan. Without the material, the plan alone is but a castle in the air-a mere possibility; whilst the material without a plan is but useless matter.