Lyell's Geology and Gothic Architecture

It seems to me a great delusion to call or suppose the imagination of a subtle fluid, or molecules penetrable with the same, a legitimate hypothesis. It is a mere _suffiction_. Newton took the fact of bodies falling to the centre, and upon that built up a legitimate hypothesis. It was a subposition of something certain. But Descartes' vortices were not an hypothesis; they rested on no fact at all; and yet they did, in a clumsy way, explain the motions of the heavenly bodies. But your subtle fluid is pure gratuitous assumption; and for what use? It explains nothing.

Besides, you are endeavouring to deduce power from mass, in which you expressly say there is no power but the _vis inertiae_: whereas, the whole analogy of chemistry proves that power produces mass.