430 
of he planetary system of course require similar correction . , . , in the 
case of Neptune .... about 122 millions of miles. The velocity of light is 
decreased by nearly 8,000 miles per second , and becomes 183,470 if based upon 
astronomical data, alone ’ (p. 48). 
“ The ‘ astronomical data ’ upon which the velocity of light has been long 
given out by astronomers as 192,000 miles per second, are (1st) the diameter 
of the earth’s orbit, depending upon its distance from the sun ; which 
distance is stated in Mr. Chambers’s Handbook (as in other astronomical 
works) to * have been ascertained with great accuracy from the transit 
of Yenus in 1769 ’ ; and (2nd) ‘ the difference in the time of the eclipses of 
Jupiter’s satellites when the earth was at its greatest [and least] distance 
from Jupiter, namely, 16' 26"= 190 millions miles (diam. of earth’s orbit) =* 
192.000 miles per second.’ — (Handb. of Ast. in loc.) 
“ On page 38 of Victoria foto Goelo, referring to the instantaneous coin- 
cidence of some bright appearances on the sun’s disk with certain magnetic 
disturbances on the earth (alluded to in Sir William Armstrong’s address to 
the British Association), the following passage occurs : — 
“ ‘ I would first beg to observe, that we seem to have an indication here, 
that electric or magnetic forces and light, probably travel with identical 
velocity. This is important in connection with Professor Wheatstone’s 
interesting experiments with the “ rotating mirror ” as to the velocity of 
electricity, afterwards applied by Foucault to measure the velocity of light. 
Mr. Hind has quoted, in his letter to the Times of 17th September, 1863, 
the results of M. Foucault’s experiments as confirming the reduced velocity of 
light, following from the newly reduced diameter of the earth’s orbit. 
He says 
“ ‘ M. Leon Foucault, of Paris, has succeeded in measuring the absolute 
velocity of light by means of the ‘ turning mirror,’ an experimental deter- 
mination of no little interest and significance. He concludes that it cannot 
differ much from 298,000,000 of French metres per second, or 185,170 
English miles, which is a notable diminution upon the velocity previously 
derived from astronomical data alone.’ 
“But some years ago, Professor 'Helmholtz wrote of these same experi- 
ments, when the velocity of light was believed to be 192,000 miles a second , — 
“‘We have thus determined in a distance of twelve feet no less than 
the velocity with which light is propagated, which is known to be nearly 
200.000 miles a second; — the distance mentioned corresponds, therefore, to the 
77 -millionth part of a second .’ 
“ ‘ At that time, it will be observed, the experiments with the rotating 
mirror were said to accord with the velocity derived from the then existing 
‘astronomical data,’ without any ‘notable diminution !’” (p. 38). 
“ I will only add that there has been a significantly marked silence, on the 
part of some journals that call themselves^/ scientific,’ as regards Mr. Hind’s 
important letter to the Times. They almost entirely ignored it ; and it is 
whispered that its publication has given offence in ‘ scientific ’ quarters. 
Heaven help us, if ‘science’ is thus to demean itself in the nineteenth 
century, in England ! But, to quote once more, ‘Neither the British press 
nor public have any vested interest in error.’ .... ‘ Unquestionably, 
science is honoured and credited in the present day, as perhaps no religion, 
even, ever was. But it should be remembered by ‘ men of science ’ that the 
worship is sincere. What is thus credited is credited as truth ; and if that 
is suppressed, ignored, or tampered with, the injury done to true science by 
those who ought to have been its guardians, will never be forgiven.’ (Viet. 
Tot. Coel., pp. 41, 51.) “ J. R. 
“ November 30th, 1863.” . 
