[228] _On the Law of Diffusion of Gases_: by Thomas Graham, M.A., F.R.S., &c.; Edinburgh Philosophical Transactions, 1832. _Sur l’Action Capillaire des Fissures, &c._: by Döbereiner; Annales de Chimie, xxiv. 332. [229] _Electro-chemical Researches on the Decompositions of the Earths, with observations on the Metals obtained from the Alkaline Earths, and on the Amalgam procured from Ammonia_: by Sir Humphry Davy; Philosophical Transactions, 1808, and collected works, vol. v. p. 102. [230] _Elements of Chemical Philosophy_: by Sir H. Davy. CHAPTER XIII. TIME.--GEOLOGICAL PHENOMENA. Time, an element in Nature’s Operations--Geological Science--Its Facts and Inferences--Nebular Hypothesis applied--Primary Formations--Plutonic and Metamorphic Rocks--Transition Series--Palæozoic Rocks--Commencement of Organic Arrangements--Existence of Phosphoric Acid in Plutonic Rocks--Fossil Remains--Coal Formation--Sandstones--Tertiary Formations--Eocene, Miocene, and Pliocene Formations--Progressive changes now apparent--General Conclusions--Physics applied in explanation. The influence of time, as an element, in producing certain structural arrangements, by modifying the operations of physical force, under whatever form it may be exerted, has scarcely been sufficiently attended to in the examination of cosmical phenomena. Every particle of matter is, as it were, suspended between the agencies to which we have been directing our attention. Under the influences of the physical powers, sometimes exerted in common, but often with a great preponderance in favour of one of them, every accumulated heap of mud or sand is slowly cohering, and assuming the form of a rock possessing certain distinguishing features, as it regards lamination, cleavage, &c. The minute particles of matter are necessarily but slightly influenced by the physical forces: their action in accordance with the laws which determine physical condition is manifested in an exceedingly modified degree. But in all the operations of nature, what is deficient in power is made up in time, and effects are produced during myriads of ages, by powers far too weak to give satisfactory results by any experiments which might be extended even over a century. If, with the eye of a geologist, we take but a cursory glance over the Earth, we shall discover that countless ages must have passed during the progress of this planet to its present state. This is a fact written by the finger of nature, in unmistakeable characters, upon the mighty tablets of her mountains.