For them, it wasn't a method of propagation, either.
The slower propagation of light in gas or water than in air or vacuum may be attributed to a greater density, or to a less rigidity, in the former case; or we may adopt the more complicated supposition that both these quantities vary, subject only to the condition which restricts the ratio of velocities to equality with the known refractive index.
The number (i) expressing the ratio of the two amplitudes is a function of the following quantities: - (T) the volume of the disturbing particle; (r) the distance of the point under consideration from it; (A) the wave-length; (b) the velocity of propagation of light; (D) and (D') the original and altered densities: of which the first three depend only upon space, the fourth on space and time, while the fifth and sixth introduce the consideration of mass.
In any case the discovery is to some extent his own, for his proof of the law is founded upon the theory that light is the propagation of the aether in straight lines from the sun or luminous body to the eye (see Light).
Here Drs Lowe and Sambon made the decisive experiments which proved that the propagation of malaria was due to the mosquito Anopheles claviger.