574 Velocity of Light . [October, 
The correctness of the result obtained for the velocity of 
light by formula a depends on the correctness of the single 
terms, of which solar distance is the most uncertain. 
I took g = 9*8088 metre (Paris), a correction (not plain 
latitude) being trifling, for radius of the earth, 6,369,829 
metres, or quadrant 10,000,000 metres. For height of the 
atmosphere i~75*4 of the radius, according to passage 
quoted from o. s. p., and for solar distance 23,730 radii, as 
appearing from the compressibility of the sea (see before), 
and from other reasons (mean motion in orbit 30071 metres 
in second), or— 
23730 x 75*4 x 84500 m = 1789242 x 84500 m — 
= 151,190,949,000 metres = 94,900,000 miles. 
about the old figure. Which brings the velocity of light 
through formula a, 305,686,029 metre a second, in complete 
agreement with the results of b. 
Having long ago characterised electricity as resulting 
from a disturbance in the distribution of weight in certain 
strata of opposite hemispheres of mass and molecule, and 
since then shown in o. s. p. the part played with regard to 
our planet by a hemispheric inequality of 1 -r 2978 of sea, 
atmosphere, and solid, answering to the inequality of solar 
distance, I pass on to Clerk Maxwell’s hypothesis of the 
eleCtro-magnetic nature of light. 
He about says : — When V, the quantity expressing the 
velocity of propagation of eleCtro-magnetic disturbance, is 
numerically equal to v, the number of eleCtro-static units of 
electricity in the eleCtro-magnetic unit, light is an eleCtro- 
magnetic disturbance propagated in the same medium if V 
equal to the velocity of light. “ Hence the agreement or 
disagreement of the values of V and v furnishes a test of the 
eledtro-magnetic theory of light.” He then gives the follow- 
ing table - 
by grating 3 than by 2, and 1*4 units less by grating 2 than by 4, and sees no 
reason but a less appropriate construction of 3 and 4. 
The difference between the 5407 and 526*9 mth. m.m. is only 13*8 units. 
Angstrom speaks of a double ray, and allows for the coming and going a 
width of 13 units, and the wave-lengths of H 2 as found vary more than 3 units. 
When we deduct 1*4 unit from the 13*8, making them 12-4, they are the 
1 -^42*6 of the 526*9. There is undoubtedly much that is oscillatory about all 
quantities connected with light, as the quotients of J? into g vary, the outer 
atmosphere is a compressor, the atmosphere is not of equal height, and we 
have from bottom to top within the atmosphere between solar and terrestrian 
gravity the prominent relations 1 4 1773, 1 ~ 1713, 1 ,4. 1743, 1 ^ 1655, &c. 
