SPONTANEOUS GENERATION.
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larger towns of the country are alone opposing this scheme compounded of fraud and folly, and it is to be feared that their political influence is quite inadequate to stand against the urgency of the great majorities of the West and South.
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SPONTANEOUS GENERATION |
By Prof. JOHN TYNDALL, F. R. S.
II.
LET us now return to London and fix our attention on the dust of its air. Suppose a room in which the house-maid has finished her work to be completely closed, with the exception of an aperture in a shutter through which a sunbeam enters and crosses the room. The floating dust reveals the track of the light. Let a lens be placed in the aperture to condense the beam. Its parallel rays are now converged to a cone, at the apex of which the dust is raised to almost unbroken whiteness by the intensity of its illumination. Defended from all glare, the eye is peculiarly sensitive to this scattered light. The floating dust of London rooms is organic, and may be burned without leaving visible residue. The action of a spirit-lamp flame upon the floating matter has been elsewhere thus described:
- ↑ "Fragments of Science," fifth edition, pp. 128, 129.