52 Scientific Intelligence. 
SCIENTIFIC INTELLIGENCE. 
IL CHEMISTRY AND PHYSICS. 
velocity of light. His researches, which have extended over a 
peri 
at Mon erien. stance between as carefully 
measured and found to be 10310 meters, with a probable error of 
less than ten meters. Th 1 was carried upon the arbor of 
the minute-hand of an improved clock-work. Three of these 
wheels were made u having respectively 104, 116, and 140 
teeth o th rk an electric apparatus to register the 
velocity of rotation was attached, and also the means for regula- 
ting its motion, a versing its ty of 
700 to 800 revolutions per second could be thus obtained, whic 
was uniform, an ctly under control e registering ap- 
rver, marked the nts of eclipse. The calcium-light was 
generally employed as the source of illumination, though a simple 
eum lamp was also occasionally u thousand 
lst order. 2dorder. 3dorder. 4thorder. 5thorder. 6thorder. ‘th order. 
_.-- 302,600 297,300 298,500 298,800 297,500 300,400 
Sees (17) (236) (876) (480) (91) (27) 
The numbers in parentheses express the relative value of the cor- 
neg observations; and are obtained by dividing by 10 the 
product obtained by multiplying the number of observations by 
2n—1 (n being the order of the eclipse) and by 1, 2, 3 or 4, 0c- 
cording as the observation was recorded as fair, good, very good, 
or excellent. The mean result is 298,400 kilometers; multiplying 
this result by 1:0003, the refractive index of air, 298,500 kilome- 
is obtained as the velocity of light ina vacuum. This, Cornu 
believes, is accurate to x3, of its value. It is a close approxima- 
i a 5 eon Sa é i rs 
Se Oe ee ee ae ee ee ae 
